Ventricular assist device and its control unit

Abstract

The invention provides a ventricular assist device and a control unit thereof, the control unit controls to apply a first phase current to a first three-phase winding, an axial component force generated by the first phase current moves an impeller from a static position to a first axial position, and a radial component force generated by the first phase current drives the impeller to rotate; and a second phase current is controlled to be applied to the second three-phase winding, the first phase current is reduced, the sum of axial forces generated by the first phase current and the second phase current is zero so that the impeller can be kept at the first axial position, and the sum of radial component forces generated by the first phase current and the second phase current enables the impeller to rotate at the target rotating speed. The winding unit in the motor is obliquely arranged, so that the control unit can control the axial position and the rotating speed of the impeller by adjusting the magnitude of the applied phase current, the torque and the suspension force can be directly controlled without depending on an FOC algorithm, and the motor control algorithm is simple.

Description

(19) State Intellectual Property Office (12) Invention Patent Application (10) Application Publication Number (43) Application Publication Date (21) Application Number 202511598920.2 (22) Application Date 2025.11.04 (71) Applicant Core Medical Technology (Hong Kong) Limited Address Room 1406A, 14th Floor, Huabi Bank Tower, 721-725 Nathan Road, Mong Kok, Kowloon, Hong Kong, China (72) Inventors Gao Hongwei, Yu Shunzhou (74) Patent Agency Shenzhen Kejin Intellectual Property Agency (General Partnership) 44316 Patent Attorney Meng Jie (51) Int.Cl. A61M 60 / 178 (2021.01) A61M 60 / 216 (2021.01) A61M 60 / 411 (2021.01) A61M 60 / 538 (2021.01) (54) Invention Title: Ventricular Assist Device and Control Unit Thereof (57) Abstract: This application proposes a ventricular assist device and its control unit. The control unit controls the application of a first phase current to a first three-phase winding. The axial component of the first phase current moves the impeller from a stationary position to a first axial position, and the radial component of the first phase current drives the impeller to rotate. The control unit also controls the application of a second phase current to a second three-phase winding and reduces the first phase current. The sum of the axial forces generated by the first and second phase currents is zero, thus holding the impeller at the first axial position. The sum of the radial components of the first and second phase currents rotates the impeller at a target speed. This application tilts the winding units in the motor, allowing the control unit to control the axial position and rotational speed of the impeller by adjusting the applied phase current. This enables direct control of torque and levitation force without relying on the FOC algorithm, simplifying the motor control algorithm. Claims 2 pages, Description 11 pages, Drawings 4 pages, CN 121371465 A 2026.01.23 CN 1 21 37 14 65 A 1. A control unit for a ventricular assist device, characterized in that the ventricular assist device includes a housing, an impeller disposed within the housing, and a motor for driving the impeller to rotate, the motor including a rotor and a stator, the stator including a first three-phase winding and a second three-phase winding, the first three-phase winding including n first winding units, the second three-phase winding including n second winding units, the n second winding units and the n first winding units being uniformly alternately arranged along a circle, the central axes of the n second winding units and the n first winding units sharing a common cylindrical surface, the central axes of adjacent first winding units and second winding units being inclined relative to the axial direction of the housing and in opposite directions, the n being greater than or equal to 3; the control unit is used to perform the following steps: applying a first phase current to the first three-phase winding, the axial component force generated by the first phase current driving the impeller fromThe impeller is moved from a rest position to a first axial position, and the radial component of the first phase current drives the impeller to rotate. A second phase current is applied to the second three-phase winding, and the first phase current is reduced, so that the sum of the axial components of the first phase current and the second phase current is zero, thereby holding the impeller at the first axial position. The sum of the radial components of the first phase current and the second phase current causes the impeller to rotate at a target speed. 2. The control unit according to claim 1, wherein the control unit is further configured to perform the following steps: increasing the first phase current to move the impeller from the first axial position to a second axial position, the second axial position being farther from the rest position than the first axial position. 3. The control unit according to claim 1, wherein the control unit is further configured to perform the following steps: increasing the second phase current to move the impeller from the first axial position to a third axial position, the third axial position being located between the rest position and the first axial position. 4. The control unit according to any one of claims 1-3, characterized in that the first phase current and the second phase current simultaneously control the axial position and rotational speed of the impeller; when the first phase current and the second phase current are applied simultaneously, the direction of the axial component force generated by the second phase current is opposite to the direction of the axial component force generated by the first phase current. 5. The control unit according to claim 1, characterized in that the axial position of the impeller and the rotational speed of the impeller are changed by the first phase current or the second phase current. 6. The control unit according to claim 1, characterized in that the angle of inclination of the central axis of the first winding unit relative to the axial direction of the housing is equal to or unequal to the angle of inclination of the central axis of the second winding unit relative to the axial direction of the housing. 7. The control unit according to claim 6, characterized in that the angle of inclination of the central axis of the first winding unit or the second winding unit relative to the axial direction of the housing ranges from 15° to 60°. 8. The control unit according to claim 1, characterized in that each first winding unit and each second winding unit includes stator teeth and stator coils, the stator coils being wound on the stator teeth, and the stator teeth being axially inclined relative to the housing. 9. A ventricular assist device, characterized in that the ventricular assist device comprises: a housing; an impeller disposed within the housing; and a motor for driving the impeller to rotate, the motor comprising a rotor and a stator, the stator comprising a first three-phase winding and a second three-phase winding, the first three-phase winding comprising n first winding units, the second three-phase winding comprising n second winding units, the n second winding units and the n first winding units being uniformly alternately arranged along a circle, the n first winding units being...The two winding units share a common cylindrical surface with the central axes of n first winding units, and the central axes of adjacent first winding units and the second winding unit are inclined relative to the axial direction of the housing and in opposite directions, wherein n is greater than or equal to 3; a control unit, wherein the control unit is the control unit as described in claims 1-8. 10. A medical device, characterized in that it includes a processor, a memory and a communication interface, wherein the memory stores one or more programs, and the one or more programs are executed by the processor, wherein the one or more programs include instructions for performing the execution steps of the control unit as described in any one of claims 1-8. Claims 2 / 2 pages 3 CN 121371465 A Ventricular Assist Device and Control Unit Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a ventricular assist device and its control unit. Background Art

[0002] Ventricular assist devices use magnetic levitation motors, which affect the torque and levitation force of the motor when voltage or current is applied to the stator, causing the motor to run unevenly. Therefore, the Field-Oriented Control (FOC) method is generally used for decoupling. The current is transformed into the (d, q) two-axis coordinate system via Clarke and Park, generating a control torque orthogonal current and a control levitation force DC current, so that the torque and levitation force can be controlled independently and linearly. However, FOC is computationally complex, has high requirements for the processor, and its performance largely depends on the correctness of the motor parameters. After the motor heats up, the stator resistance will increase significantly, leading to a decrease in the motor's control efficiency and control accuracy. Summary of the Invention

[0003] This application provides a ventricular assist device and its control unit, which can directly realize the control of torque and levitation force without relying on the FOC algorithm.

[0004] In a first aspect, embodiments of this application provide a control unit for a ventricular assist device. The ventricular assist device includes a housing, an impeller disposed within the housing, and a motor for driving the impeller to rotate. The motor includes a rotor and a stator. The stator includes a first three-phase winding and a second three-phase winding. The first three-phase winding includes n first winding units, and the second three-phase winding includes n second winding units. The n second winding units and the n first winding units are uniformly alternately arranged along a circle. The central axes of the n second winding units and the n first winding units are on the same cylindrical surface. The central axes of adjacent first winding units and second winding units are inclined relative to the axial direction of the housing and in opposite directions. The n is greater than or equal to 3. The control unit is used to perform the following steps: applying a first phase current to the first three-phase winding, the axial component of the first phase current driving the impeller to rotate.The impeller moves from a stationary position to a first axial position, and the radial component of the first phase current drives the impeller to rotate. A second phase current is applied to the second three-phase winding, and the first phase current is reduced. The sum of the axial components of the first phase current and the second phase current is zero, so as to keep the impeller at the first axial position. The sum of the radial components of the first phase current and the second phase current causes the impeller to rotate at the target speed.

[0005] In a second aspect, an embodiment of this application provides a ventricular assist device, the ventricular assist device comprising: a housing; an impeller disposed within the housing; a motor for driving the impeller to rotate, the motor comprising a rotor and a stator, the stator comprising a first three-phase winding and a second three-phase winding, the first three-phase winding comprising n first winding units, the second three-phase winding comprising n second winding units, the n second winding units and the n first winding units being uniformly alternately arranged along a circle, the central axes of the n second winding units and the n first winding units sharing a common cylindrical surface, the central axes of adjacent first winding units and second winding units being inclined relative to the axial direction of the housing and in opposite directions, the n being greater than or equal to 3; and a control unit, the control unit being the control unit as described in the first aspect above. Specification 1 / 11 Page 4 CN 121371465 A

[0006] In a third aspect, embodiments of this application provide a medical device, the medical device including 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 programs including instructions for performing some or all of the steps described in the method described in the first aspect above.

[0007] In a fourth aspect, embodiments of this application provide a computer-readable storage medium storing a computer program for electronic data interchange, wherein the computer program causes a computer to perform some or all of the steps described in the method described in the first aspect above.

[0008] In a fifth aspect, embodiments of this application provide a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps described in the method described in the first aspect of this application. The computer program product may be a software installation package.

[0009] The technical solution provided in this application involves a control unit that controls the application of a first-phase current to the first three-phase winding. The axial component of this first-phase current moves the impeller from a stationary position to a first axial position, and the radial component of this first-phase current drives the impeller to rotate. The control unit also controls the application of a second-phase current to the second three-phase winding and reduces the first-phase current.The sum of the axial components of the first and second phase currents is zero, so as to keep the impeller in the first axial position. The sum of the radial components of the first and second phase currents rotates the impeller at the target speed. In this application, the winding unit in the motor is tilted so that the control unit can control the axial position and rotation speed of the impeller by adjusting the applied phase current. It can directly control the torque and levitation force without relying on the FOC algorithm, which simplifies the motor control algorithm and avoids the decrease in motor control efficiency and control accuracy due to motor parameter errors. Brief Description of the Drawings

[0010] In order to more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1 is a structural schematic diagram of a ventricular assist device provided in an embodiment of this application; Figure 2 is a schematic diagram of a stator structure provided in an embodiment of this application; Figure 3 is a top view of a stator structure provided in an embodiment of this application; Figure 4 is a decomposition schematic diagram of the force generated when a phase current is applied to a winding unit provided in an embodiment of this application; Figure 5 is a flowchart of the execution steps of a control unit provided in an embodiment of this application; Figure 6 is a schematic diagram of an impeller in a second axial position provided in an embodiment of this application; Figure 7 is a schematic diagram of an impeller in a third axial position provided in an embodiment of this application; Figure 8 is a structural schematic diagram of a medical device provided in an embodiment of this application. Detailed Description

[0012] In order for those skilled in the art to better understand the technical solutions of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the description of the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a particular order. Furthermore, the terms "comprising" and "having," 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 these processes, methods, products, or devices.

[0014] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with an embodiment may include...Included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0015] The medical device involved in this application may be a ventricular assist device (VAD), such as an implantable ventricular assist device, a biventricular assist device, etc.; the ventricular assist device may be used for the left heart, the right heart, or both hearts; the ventricular assist device may include at least one blood pump, wherein the blood pump may be a magnetic levitation pump, and the following description uses a magnetic levitation pump as an example.

[0016] As shown in FIG1, the ventricular assist device 100 includes a housing, an impeller 20, and a motor 30. The impeller 20 is located inside the housing and is capable of levitation and rotation relative to the housing. The housing has a chamber 10, the impeller 20 is housed in the chamber 10, and is capable of levitation and rotation within the chamber 10. The housing is also provided with a fluid inlet 14 and a fluid outlet 15 communicating with the chamber 10.

[0017] The housing includes a first sidewall 11 and a second sidewall 12 opposite to the first sidewall 11; the motor 30 includes a stator 31 and a rotor 32 arranged on both sides of the first sidewall 11, with the rotor 32 located between the first sidewall 11 and the second sidewall 12. The stator 31 can drive the rotor 32 to levitate and rotate. Specifically, the rotor 32 is a permanent magnet, and in some embodiments, the rotor 32 is a Heilbeck array magnet. The stator 31 is located outside the chamber 10, and the corresponding rotor 32 is located inside the chamber 10. In the illustrated embodiment, the first sidewall 11 is the inner wall of the housing away from the stator 31, and the second sidewall 12 is the inner wall of the housing close to the stator 31. The impeller 20 is connected to the rotor 32, and the impeller 20 can levitate and rotate with the rotor 32. In the illustrated embodiment, the rotor 32 is housed within the impeller 20, which prevents corrosion of the rotor 32 by blood; in other embodiments, the rotor 32 is fixed to the surface of the impeller 20; the connection method between the rotor 32 and the impeller 20 is sufficient to achieve stable levitation and rotation of the impeller 20 with the rotor 32, and is not limited here.

[0018] The rotor 32 may be composed of multiple magnets, which are arranged at equal angular intervals along the same circle. Adjacent magnets have different magnetic poles. That is, magnets with the N pole facing the motor 30 and magnets with the S pole facing the motor 30 are alternately arranged at equal angular intervals along the same circle.

[0019] The stator 31 includes a first three-phase winding and a second three-phase winding. The first three-phase winding includes n first winding units, and the second three-phase winding includes n second winding units. The n second winding units and n first winding units are evenly alternately arranged along a circle, where n is greater than or equal to 3.

[0020] Specifically, three winding units form a three-phase winding. The motor 30 is driven by inputting three-phase alternating current (AC) into the three-phase winding, with a phase difference of 120 degrees between the phases. As shown in Figures 2-3, winding units 3101, 3103, and 3105 are designated as the first winding unit, forming the first three-phase winding; winding units 3102, 3104, and 3106 are designated as the second winding unit, forming the second three-phase winding. Adjacent first and second winding units are spaced 120 degrees apart. The first three-phase winding can independently control the rotation and levitation of the rotor 32, and the second three-phase winding can also independently control the rotation and levitation of the rotor 32.

[0021] The U-phase, V-phase, and W-phase winding units in the first three-phase winding are respectively arranged opposite to the U-phase, V-phase, and W-phase winding units in the second three-phase winding. That is, the U-phase winding unit of the first three-phase winding is opposite to the U-phase winding unit of the second three-phase winding, the V-phase winding unit of the first three-phase winding is opposite to the V-phase winding unit of the second three-phase winding, and the W-phase winding unit of the first three-phase winding is opposite to the W-phase winding unit of the second three-phase winding. As shown in Figure 3, winding unit 3101 is opposite to winding unit 3104, winding unit 3102 is opposite to winding unit 3105, and winding unit 3103 is opposite to winding unit 3106.

[0022] For example, each first winding unit and each second winding unit includes stator teeth and stator coil 312, with the stator coil 312 wound on the stator teeth. The stator teeth include an iron core 3111 and a pole shoe 3112. One end of the iron core 3111 is fixedly connected to the pole shoe 3112. The stator coil 312 is wound around the periphery of the iron core 3111, thereby realizing the installation of the stator coil 312 on the stator teeth. The stator coil 312 can control the rotational speed and levitation height of the rotor 32.

[0023] The stator 31 also includes a yoke plate 313. The yoke plate 313 is generally annular. The first winding unit and the second winding unit are both disposed on the yoke plate 313. The stator teeth of the first winding unit and the second winding unit are both fixed on the yoke plate 313. Specifically, the end of the iron core 3111 away from the pole shoe 3112 is fixed to the yoke plate 313.

[0024] The ventricular assist device 100 also includes a control unit 33 and a plurality of Hall sensors 40, which are connected to the control unit 33. The control unit 33 controls the rotational speed and levitation height of the rotor 32 by controlling the magnitude and phase of the current flowing through the stator 31. Specifically, the control unit 33 adjusts the current flowing through the winding unit (with...) in real time based on feedback detection signals.The current phase and current amplitude of the stator coil 312 are controlled to control the levitation height and rotational speed of the rotor 32, so that the rotor 32 rotates at a preset axial position. Multiple Hall sensors 40 are used to detect the levitation height of the rotor 32 relative to the stator 31 and the rotational speed of the rotor 32.

[0025] 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 via an interface to collect at least one data of the motor 30. The at least one data may include the measured current flowing through the stator 31, the motor speed, the pressure difference across the pump, the flow pulsation, the fluid velocity, etc.

[0026] For example, the control unit 33 is configured as a plate, specifically, it can be configured as a circular plate-shaped PCB circuit board. Each stator tooth passes through the control unit 33 and fixes the mounting position of the control unit 33 so that the control unit 33 is arranged opposite to the rotor 32. Specifically, each iron core 3111 passes through the control unit 33, which is supported above the stator coil 312 and electrically connected to it, thereby achieving the installation and fixation of the control unit 33. In the illustrated embodiment, multiple Hall sensors 40 are disposed on the upper surface of the control unit 33 and electrically connected to it. The multiple Hall sensors 40 are arranged symmetrically in a circle. The Hall sensors 40 are disposed between every two adjacent stator teeth. The multiple Hall sensors 40 are opposite to the rotor 32 and can monitor the suspension height of the rotor 32 relative to the stator 31 and the rotation speed of the rotor 32 in real time.

[0027] Wherein, the central axes of the n second winding units and the n first winding units are on the same cylindrical surface. The central axes of adjacent first winding units and second winding units are inclined relative to the axial direction of the housing and the inclination directions are opposite. In Figure 1, line O is the axial direction of the housing, line P is the radial direction of the housing, and the radial direction of the housing is perpendicular to the axial direction. The axial direction and radial direction mentioned in this article are both the axial direction and the radial direction of the housing.

[0028] Specifically, the winding units in the first three-phase winding have the same tilt angle relative to the axial direction, and the winding units in the second three-phase winding have the same tilt angle relative to the axial direction.

[0029] Further, the tilt angle of the central axis of the first winding unit relative to the axial direction of the housing is equal to the tilt angle of the central axis of the second winding unit relative to the axial direction of the housing. For example, the first winding unit is tilted at a first angle relative to the axial direction of the housing, that is, the central axis of the first winding unit is tilted at a first angle relative to the axial direction of the housing. The second winding unit is tilted at a second angle relative to the axial direction of the housing, that is, the central axis of the second winding unit is tilted at a second angle relative to the axial direction of the housing. Wherein, the first angle and the second angle are equal, such as both being set to 30°, 45°, 60°, etc. That is, the central axes of adjacent first winding units and second winding units are arranged axially symmetrically. Specification 4 / 11 pages 7 CN 121371465 A

[0030] For example, the first angle and the second angle are not equal. To overcome the gravity of the impeller 20, the first angle can be set to be greater than the second angle, such as setting the first angle to 60° and the second angle to 45°; or the first angle can be set to 45° and the second angle to 30°.

[0031] Wherein, the axial tilt angle between the central axis of the first winding unit and the second winding unit and the housing is in the range of 15°~60°, that is, the first angle and the second angle are less than 60°, so that the component force generated by the phase current applied by the control unit 33 to the first three-phase winding in the axial direction is the axial magnetic levitation force, which controls the impeller 32 to move away from the stator 31; the component force generated by the phase current applied by the control unit 33 to the second three-phase winding in the axial direction is the axial magnetic levitation force, which can control the impeller 32 to move closer to the stator 31. Simultaneously, the phase currents applied to the first three-phase winding and / or the second three-phase winding generate a component force (torque force) in the radial direction. This component force acts on the rotor 32, which can control the rotation of the impeller 32.

[0032] For example, as shown in FIG4, taking winding unit 3101 and winding unit 3104 as examples, the radial inclination angle of the central axis of the first winding unit relative to the housing is α, and α is complementary to the first angle; the radial inclination angle of the central axis of the second winding unit relative to the housing is β, and β is complementary to the second angle. Specifically, the yoke plate 313 is perpendicular to the axial direction of the housing; the angle between the central axis of the first winding unit and the yoke plate 313 is α, and the angle between the central axis of the second winding unit and the yoke plate 313 is β. The control unit 33 applies a first phase current to the first three-phase winding and a second phase current to the second three-phase winding, respectively. The first phase current flowing into the first winding unit generates a first Lorentz force F1, and the second phase current flowing into the second winding unit generates a second Lorentz force F2. According to the force decomposition, the component of the first Lorentz force F1 on the horizontal axis (axial direction) is F1*sinα, and the component on the vertical axis (radial direction) is F1*cosα; the component of the second Lorentz force F2 on the horizontal axis (axial direction) is F2*sinβ, and the component on the vertical axis (radial direction) is F2*cosβ. When the first phase current and the second phase current are applied simultaneously, the force acting on the impeller 20 in the axial direction is F1*sinα-F2*sinβ; the force acting on the impeller 20 in the radial direction is T=F1*cosα+F2*cosβ.

[0033] Currently, in motors such as three-phase brushless direct current motors (BLDC) and permanent magnet synchronous motors, the control unit 33 generally uses the field-oriented control (FOC) method.To control the start and operation of motor 30, the measured three-phase current is first transformed into a two-axis coordinate system via Clarke and Park transformations to generate quadrature and direct current. Then, the measured quadrature and direct currents are compared with their set values, and the difference is input to the PI controller, which outputs the corresponding voltages Vq and Vd. These are then transformed into three-phase voltages via inverse Clarke and Park transformations and input to the inverter. Control unit 33 can increase or decrease the magnetic flux between rotor 32 and stator 31 by controlling the direct current to control the axial position of impeller 20, and control the rotational torque of impeller 20 by controlling the quadrature current. However, the FOC algorithm is computationally complex, places high demands on the processor, and its performance largely depends on the accuracy of the motor parameters. After the motor heats up, the stator resistance increases significantly, leading to a decrease in motor control efficiency and accuracy.

[0034] Based on this, this application improves the motor structure by tilting the winding unit in the motor 30, so that the control unit 33 can control the axial position and rotation speed of the impeller 20 by adjusting the magnitude of the applied phase current, without needing to perform Clarke and Park transformations on the phase current to generate orthogonal current and DC current in the two-axis coordinate system. By controlling the suspension and rotation of the impeller 20 through the FOC method of controlling the orthogonal current and DC current, the complexity of motor control can be greatly reduced, and the influence of the FOC algorithm on motor control can be avoided.

[0035] Specifically, as shown in FIG5, the control unit 33 executes the following steps to control the operation of the motor 30.

[0036] S510, At the first moment, a first phase current is applied to the first three-phase winding. The axial component force generated by the first phase current moves the impeller from the stationary position to the first axial position, and the radial component force generated by the first phase current drives the impeller to rotate.

[0037] When the motor 30 is not started or running, the impeller 20 rests on the inner surface of one side of the housing due to gravity, specifically on the inner surface of the housing near the stator 31. Upon receiving a start command to start the impeller 20, the control unit 33 controls the impeller 20 to gradually increase its rotation to a set target speed, and during the rotation, suspends the impeller 20 to a preset axial position so that the impeller 20 is in a non-contact state with the housing, thereby realizing the non-contact bearing of the magnetic levitation motor. Since the first three-phase winding and the second three-phase winding can independently control the levitation and rotation of the impeller 20, when the motor 30 needs to be started, the control unit 33 can directly apply the first phase current to the first three-phase winding to move the impeller 20 from the stationary position to the first axial position, while rotating during the movement. At the stationary position, one side of the impeller 20 rests on the inner surface of the housing.

[0038] The control unit 33 can set the magnitude of the first phase current according to the preset first axial position. Since the first three-phase winding is tilted at a first angle, the component of the Lorentz force generated by the first phase current on the horizontal axis (the levitation force that controls the levitation of the impeller 20) drives the impeller to axial displacement. This component force is axial and pushes the impeller 20 to move away from the stationary position. The component of the Lorentz force generated by the first phase current on the vertical axis (the torque force that controls the rotation of the impeller 20) drives the impeller to rotate. This component force drives the impeller 20 to rotate clockwise.

[0039] In this application, the control unit 33 can control the levitation and rotation of the impeller 20 by independently controlling the phase current applied to the first three-phase winding. Moreover, the control unit 33 can directly control the axial position and rotation speed of the impeller 20 by controlling the magnitude of the phase current, without the need for complex FOC algorithm control.

[0040] S520. Apply a second phase current to the second three-phase winding and reduce the first phase current. The sum of the axial components of the first phase current and the second phase current is zero, so as to keep the impeller at the first axial position. The sum of the radial components of the first phase current and the second phase current causes the impeller to rotate at the target speed.

[0041] Wherein, the second three-phase winding is tilted at a second angle, so that the component of the applied second phase current on the horizontal axis (axial direction) is axially downward. The impeller in the magnetic levitation pump needs to be kept suspended in the housing during rotation. Therefore, when the impeller 20 is suspended to the preset first axial position, in order to keep the impeller 20 at the first axial position, the control unit 33 can apply a second phase current to the second three-phase winding so that the component of the first phase current in the axial direction is equal in magnitude and opposite in direction to the component of the second phase current, so that the impeller 20 is kept suspended at the first axial position.

[0042] According to the electromagnetic force equation F=B*I*L, the first phase current generates the Lorentz force, and the second phase current generates the Lorentz force. Since the angle between the winding unit and the yoke plate 313 in the first three-phase winding is α, by decomposing the Lorentz force F1, it can be seen that the axial upward component of the impeller 20 is F1*sinα=I1*sinα*B*L, and the radial component of the impeller 20 is F1*cosα=I1*cosα*B*L, where B is the magnetic induction intensity of the rotor 32, and L is the distance between the rotor 32 and the stator 31. The angle between the winding unit and the yoke plate 313 in the second three-phase winding is β. By decomposing the Lorentz force F2, it can be seen that the axial upward component of the impeller 20 is F2*sinβ=I2*sinβ*B*L, and the radial component of the impeller 20 is F2*cosβ=I2*cosβ*B*L, where B is the magnetic induction intensity of the rotor 32, and L is the distance between the rotor 32 and the stator 31.

[0043] The control unit 33 controls the magnetic levitation force (axial force) and torque force between the rotor 32 and the stator 31 by increasing or decreasing the applied phase current. The magnetic levitation force and torque force can be expressed as follows: Specification 6 / 11 page 9 CN 121371465 A

[0044]

[0045] The magnetic flux density generated by the magnetic body of the rotor 32, r is the radius of the magnetic body of the rotor 32, P is the number of pole pairs of the magnetic body of the rotor 32, N is the number of turns of the stator coil 312, and I is the phase current applied by the control unit 33.

[0046] Therefore, the magnetic levitation force and torque force generated by the first phase current are respectively: ,

[0047] The magnetic levitation force and torque force generated by the second phase current are respectively: ,

[0048] Wherein, the first three-phase winding can independently control the levitation and rotation of the impeller 20, the second three-phase winding can also independently control the levitation and rotation of the impeller 20, and the control unit 33 can also simultaneously apply phase current to the first three-phase winding and the second three-phase winding to control the levitation and rotation of the impeller 20. When the control unit 33 simultaneously applies the first phase current to the first three-phase winding and the second phase current to the second three-phase winding, the first phase current and the second phase current simultaneously control the axial position and rotational speed of the impeller. The magnetic levitation force and torque generated by the first phase current, and the magnetic levitation force and torque generated by the second phase current, act simultaneously on the impeller 20, so that the magnetic levitation force and torque force borne by the impeller 20 are respectively:

[0049]

[0050] Because the first three-phase winding and the second three-phase winding are inclined, when the first phase current and the second phase current are applied simultaneously, the direction of the axial force generated by the second phase current is opposite to the direction of the axial force generated by the first phase current. In order to keep the impeller 20 in the first axial position, when the impeller 20 is suspended in the first axial position, the control unit 33 applies the second phase current to the second three-phase winding and reduces the magnitude of the first phase current, so that the magnetic levitation force borne by the impeller 20 is 0.

[0051] Wherein, changing the axial position of the impeller 30 by the first phase current or the second phase current will change the rotational speed of the impeller 20. The phase current applied by the control unit 33 will simultaneously affect the axial position and rotational speed of the impeller 20. Therefore, in order to keep the impeller 20 suspended in the first axial position while rotating at the target speed, the control unit 33 can calculate the magnitude of the second phase current and the magnitude of the first phase current according to α and β. Based on the calculated magnitude, the control unit 33 simultaneously applies the second phase current to the second three-phase winding and reduces the first phase current to that value.

[0052] During the rotation of the impeller 20, the control unit 33 can directly control the axial position and rotational speed of the impeller 20 by adjusting the first phase current applied to the first three-phase winding and the second phase current applied to the second three-phase winding. This allows for direct control of torque and levitation force without relying on the FOC algorithm, simplifying the motor control algorithm and avoiding the need for additional control.Motor parameter errors lead to a decrease in the control efficiency and control accuracy of motor 30.

[0053] For example, the control unit is also used to perform the following steps: increasing the first phase current and moving the impeller from the first axial position to a second axial position, the second axial position being farther from the rest position than the first axial position.

[0054] Non-contact impeller suspension technology solves the support and energy consumption problems in highly mechanical designs, allowing the impeller 20 to suspend and rotate within the housing during operation. Fluid is pumped through the gap between the surface of the impeller 20 and the inner wall surface of the housing, and the blood passing through this gap may contain particles. These particles can form solid or semi-solid deposits in the patient's body, leading to the formation of thrombi. The formed thrombi can remain on the wall surface of the impeller or housing and hinder its operation, which is harmful or even fatal to the patient. Therefore, during the operation of the ventricular assist device 100, in order to prevent the formation of thrombi, the control unit 33 can move the impeller 20 in the axial range to increase the gap between the impeller 20 and the housing.

[0055] Specifically, as shown in FIG6, the impeller position is moved to the second axial position. When it is necessary to move the impeller 20 away from the stator 31 so that the axial distance between the impeller 20 and the first sidewall 11 is greater than the axial distance between the impeller 20 and the second sidewall 12, the control unit 33 can directly increase the first phase current to increase the axial upward magnetic levitation force, so that the magnetic levitation force borne by the impeller 20 is >0, and move the impeller 20 from the first axial position away from the stator 31 to the second axial position.

[0056] The control unit is also used to perform the following steps: increase the second phase current, move the impeller from the first axial position to the third axial position, the third axial position being located between the stationary position and the first axial position.

[0057] As shown in FIG7, the impeller is moved to the third axial position. When it is necessary to move the impeller 20 closer to the stator 31, so that the axial distance between the impeller 20 and the first sidewall 11 is less than the axial distance between the impeller 20 and the second sidewall 12, the control unit 33 can directly increase the second phase current to increase the axial downward magnetic levitation force, so that the magnetic levitation force borne by the impeller 20 is <0, and move the impeller 20 from the first axial position to the third axial position closer to the stator 31. Therefore, the axial displacement of the impeller 20 can be directly controlled by simply controlling the phase current flowing through the first three-phase winding or the second three-phase winding, without the need to execute a complex control algorithm.

[0058] Wherein, the first axial position is located near the center of the chamber 10, and the second and third axial positions are within the allowable safe range.

[0059] It can be seen that this application proposes a control unit to control the application of the first phase current to the first three-phase winding.The axial force generated by the first phase current moves the impeller from a stationary position to a first axial position, and the torque generated by the first phase current drives the impeller to rotate. The second phase current is applied to the second three-phase winding, and the first phase current is reduced. The sum of the axial forces generated by the first and second phase currents is zero, so that the impeller is held in the first axial position. The sum of the torques generated by the first and second phase currents rotates the impeller at the target speed. This application tilts the winding units in the motor 30, allowing the control unit 33 to control the axial position and rotational speed of the impeller 20 by adjusting the applied phase current. This enables direct control of torque and levitation force without relying on the FOC algorithm, simplifying the motor control algorithm and avoiding a decrease in motor control efficiency and accuracy due to motor parameter errors.

[0060] The above mainly describes the solution of the embodiment of this application from the perspective of the method execution process. It is understood that, in order to achieve the above functions, the network device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps described in conjunction with the embodiments provided herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0061] For example, this application provides a control unit including one or more processors for performing the steps shown in FIG. 5 above.

[0062] For example, this application provides a ventricular assist device, which includes: a housing; an impeller disposed within the housing; a motor for driving the impeller to rotate, the motor including a rotor and a stator, the stator including a first three-phase winding and a second three-phase winding, the first three-phase winding including n first winding units, the second three-phase winding including n second winding units, the n second winding units and the n first winding units being uniformly alternately arranged along a circle, the central axes of the n second winding units and the n first winding units sharing a common cylindrical surface, the central axes of adjacent first winding units and second winding units being inclined relative to the axial direction of the housing and in opposite directions, the n being greater than or equal to 3; and a control unit for performing the steps described in FIG. 5 above.

[0063] For example, this application also provides a medical device, which includes the above-described control unit 33 or ventricular assist device 100.

[0064] The control unit 33 of each of the above schemes has the function of implementing the corresponding steps performed by the medical device in the above method; the function can be implemented by hardware or by hardware executing corresponding software.

[0065] Please refer to FIG8, FIG8 is a schematic diagram of the structure of a medical device provided in an embodiment of this application. The medical device includes: 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.

[0066] The above program includes instructions for performing the following steps: applying a first phase current to a first three-phase winding, the axial component of the first phase current moves the impeller from a stationary position to a first axial position, and the radial component of the first phase current drives the impeller to rotate; applying a second phase current to a second three-phase winding and reducing the first phase current, the sum of the axial components of the first phase current and the second phase current is zero, so as to hold the impeller at the first axial position, and the sum of the radial components of the first phase current and the second phase current causes the impeller to rotate at a target speed.

[0067] All relevant content of each scenario involved in the above method embodiments can be referenced to the functional description of the corresponding functional module, and will not be repeated here.

[0068] It should be understood that the above memory may include read-only memory and random access memory, and provide instructions and data to the processor. A part of the memory may also include non-volatile random access memory. For example, the memory may also store device type information.

[0069] In the embodiments of this application, the processor of the above device may be a central processing unit (CPU), which may 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 gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0070] It should be understood that "at least one" in the embodiments of this application refers to one or more, and "more" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "OR" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c.An item (item) 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.

[0071] And, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the order, timing, priority, or importance of multiple objects. For example, first information and second information are only used to distinguish different information, and do not indicate the difference in the content, priority, sending order, or importance of these two types of information.

[0072] In the implementation process, each step of the above method can be completed by the integrated logic circuit of the hardware in the processor or by the instructions in the form of software. The steps of the method disclosed in the embodiments of this application can be directly reflected as being executed by the hardware processor, or being executed by a combination of hardware and software units in the processor. The software unit can be located in random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, registers, and other mature storage media in the art. The storage medium is located in the memory, and the processor executes the instructions in the memory, combining with its hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0073] This application embodiment also provides a computer storage medium, wherein the computer storage medium stores a computer program for electronic data interchange, the computer program causing the computer to perform some or all of the steps of any of the methods described in the above method embodiments.

[0074] This application embodiment also provides a computer program product, the computer program product including a non-transitory computer-readable storage medium storing a computer program, the computer program being operable to cause the computer to perform some or all of the steps of any of the methods described in the above method embodiments. The computer program product can be a software installation package.

[0075] It should be noted that, for the foregoing method embodiments, for the sake of simplicity, they are all described as a series of actions, but those skilled in the art should know that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0076] In the above embodiments, the descriptions of each embodiment have different focuses. Parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.

[0077] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of the above units is merely a logical...The functional division can be implemented in other ways, such as combining or integrating multiple units or components into another system, or ignoring or not executing some features. Furthermore, the coupling or direct coupling or communication connection shown or discussed can be indirect coupling or communication connection through some interfaces, devices, or units, and can be electrical or other forms.

[0078] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments of this application.

[0079] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units.

[0080] If the integrated units described above are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable memory. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or TRP, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The memory described on pages 10 / 11 of the previous specification, CN 121371465 A, includes: USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard disk, magnetic disk, or optical disk, and other media that can store program code.

[0081] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable memory, which may include: flash drive, ROM, RAM, magnetic disk, or optical disk, etc.

[0082] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application. Specification 11 / 11 pages 14 CN121371465 A Fig. 1 Fig. 2 DESCRIPTION DRAWING Page 1 / 4 15 CN 121371465 A Fig. 3 Fig. 4 DESCRIPTION DRAWING Page 2 / 4 16 CN 121371465 A Fig. 5 Fig. 6 Fig. 7 DESCRIPTION DRAWING Page 3 / 4 17 CN 121371465 A Fig. 8 DESCRIPTION DRAWING Page 4 / 4 18 CN 121371465 A Abstract The present application proposes a ventricular assist device and a control unit thereof. The control unit controls the application of a first phase current to a first three-phase winding. An axial component force generated by the first phase current moves the impeller from a stationary position to a first axial position, while a radial component force generated by the first phase current drives the impeller to rotate. The control unit further controls the application of a second phase current to a second three-phase winding and reduces the first phase current. The sum of the axial forces generated by the first phase current and the second phase current is zero, thereby maintaining the impeller at the first axial position. The sum of the radial component forces generated by the first phase current and thesecond phase current rotates the impeller at a target speed. In the present application, the winding units in the motor are arranged obliquely, allowing the control unit to adjust the axial position and rotational speed of the impeller by modifying the applied phase currents. This enables direct control of torque and suspension force without relying on the FOC algorithm, simplifying the motor control algorithm.

Claims

1. A control unit for a ventricular assist device, characterized in that, The ventricular assist device includes a housing, an impeller disposed within the housing, and a motor driving the impeller to rotate. The motor includes a rotor and a stator. The stator includes a first three-phase winding and a second three-phase winding. The first three-phase winding includes n first winding units, and the second three-phase winding includes n second winding units. The n second winding units and the n first winding units are evenly alternately arranged along a circle. The central axes of the n second winding units and the n first winding units share a cylindrical surface. The central axes of adjacent first winding units and second winding units are inclined relative to the axial direction of the housing in opposite directions. The number n is greater than or equal to 3. The control unit is used to perform the following steps: A first phase current is applied to the first three-phase winding. The axial component of the first phase current moves the impeller from a stationary position to a first axial position. The radial component of the first phase current drives the impeller to rotate. A second phase current is applied to the second and third phase windings, and the first phase current is reduced. The sum of the axial components of the first and second phase currents is zero, so as to keep the impeller at the first axial position. The sum of the radial components of the first and second phase currents causes the impeller to rotate at the target speed.

2. The control unit according to claim 1, characterized in that, The control unit is also configured to perform the following steps: Increase the first phase current to move the impeller from the first axial position to a second axial position, the second axial position being farther from the rest position than the first axial position.

3. The control unit according to claim 1, characterized in that, The control unit is also configured to perform the following steps: Increase the second phase current to move the impeller from the first axial position to the third axial position, the third axial position being located between the rest position and the first axial position.

4. The control unit according to any one of claims 1-3, characterized in that, The first phase current and the second phase current simultaneously control the axial position and rotational speed of the impeller; When the first phase current and the second phase current are applied simultaneously, the direction of the axial component force generated by the second phase current is opposite to the direction of the axial component force generated by the first phase current.

5. The control unit according to claim 1, characterized in that, The axial position of the impeller and the rotational speed of the impeller can be changed by the first phase current or the second phase current.

6. The control unit according to claim 1, characterized in that, The angle at which the central axis of the first winding unit is tilted relative to the axial direction of the housing is equal to or different from the angle at which the central axis of the second winding unit is tilted relative to the axial direction of the housing.

7. The control unit according to claim 6, characterized in that, The angle of inclination of the central axis of the first winding unit or the second winding unit relative to the axial direction of the housing ranges from 15° to 60°.

8. The control unit according to claim 1, characterized in that, Each of the first winding unit and each of the second winding units includes a stator tooth and a stator coil, the stator coil being wound on the stator tooth, the stator tooth being axially inclined relative to the housing.

9. A ventricular assist device, characterized in that, The ventricular assist device includes: case; An impeller disposed within the housing; The motor that drives the impeller to rotate includes a rotor and a stator. The stator includes a first three-phase winding and a second three-phase winding. The first three-phase winding includes n first winding units, and the second three-phase winding includes n second winding units. The n second winding units and the n first winding units are evenly alternately arranged along a circle. The central axes of the n second winding units and the n first winding units are on the same cylindrical surface. The central axes of adjacent first winding units and second winding units are inclined relative to the axial direction of the housing and in opposite directions. The n is greater than or equal to 3. The control unit is the control unit as described in claims 1-8.

10. A medical device, characterized in that, The device includes a processor, a memory, and a communication interface. The memory stores one or more programs, which are executed by the processor. The one or more programs include instructions for performing the steps of the control unit as described in any one of claims 1-8.

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