Method for starting blood pump with electrical failure

Abstract

A method of starting an implantable blood pump including a first stator and a second stator includes detecting an electrical fault in one of a group consisting of the first stator and the second stator and initiating starting of the first stator and the second stator in response to the electrical fault.

Description

Technical Field

[0001] The present invention relates to a method and a system for priming a blood pump. Background Art

[0002] An implantable blood pump used as a mechanical circulatory support device contains a pumping mechanism that moves blood from the heart to the rest of the body. The pumping mechanism may be a centrifugal flow pump, such as the one manufactured by HeartWare, Inc., Miami Lakes, Florida, USA. Pump. Further discussed in U.S. Pat. No. 8,512,013 Pump, the disclosure of which is hereby incorporated by reference in its entirety. In operation, the blood pump draws blood from a source, such as the right ventricle, left ventricle, right atrium, or left atrium of a patient's heart, and pushes the blood into an artery, such as the patient's ascending aorta or a peripheral artery.

[0003] For example Known blood pumps generally include an impeller positioned within a pump housing to propel blood through the housing from an inflow end to an outflow end. The pump includes dual stators, one located upstream of the impeller and one located downstream of the impeller, configured to rotate the impeller to propel the blood. A control system typically controls the operation of a power source (power supply) in communication with the stators to drive the impeller at a set speed and thereby provide a constant pumping action.

[0004] When the blood pump is shut down and / or operation of the impeller is temporarily suspended, it is desirable to start or resume operation of the pump to provide cardiac assistance to the patient as quickly and efficiently as possible. However, starting the impeller can be difficult, especially when the impeller is resting on the housing of the pump. At least one known method of starting a blood pump includes a ramp-up phase, a reversing phase, and a speed phase in which the speed of the pump is locked for a period of time and then the speed is increased. Another known method of starting a blood pump includes using only a single stator when a fault is detected in the second stator, which increases the difficulty of successful starting. Summary of the invention

[0005] The present invention advantageously provides a method and system for priming a blood pump.

[0006] In one aspect, the present disclosure provides a method of starting an implantable blood pump. The method includes gradually increasing a motor speed from an inactive state to a first speed during a first time period. Applying a predetermined maximum voltage during the gradual increase in motor speed. Transitioning from the gradual increase in motor speed to closed-loop speed control to achieve an operating speed that is greater than the first speed.

[0007] In another aspect, the method further comprises bypassing the commutation phase.

[0008] In another aspect, the method further includes maintaining the voltage below a predetermined maximum voltage threshold.

[0009] In another aspect, the transition of the motor speed from the inactive state to the operating speed occurs within a startup duration of less than 8 seconds.

[0010] In another aspect, the method further comprises moving an impeller of the blood pump from a starting position in which the impeller is in contact with the disk to an operating position in which the impeller is removed from the disk.

[0011] In another aspect, the method further comprises generating a non-linear frequency ramp when gradually increasing the motor speed from the inactive state to the first speed.

[0012] In another aspect, the method further includes applying a predetermined maximum voltage to a plurality of coils of a stator disposed within the implantable blood pump while gradually increasing the motor speed from an inactive state to a first speed.

[0013] On the other hand, the inactive state includes a speed of zero, and a first speed between 100 RPM and 2000 RPM.

[0014] In another aspect, the first time period is between 2 seconds and 3 seconds, and the second time period is less than one second.

[0015] In one aspect, a method of starting an implantable blood pump comprising a first stator and a second stator comprises detecting an electrical fault in one of the group consisting of the first stator and the second stator. In response to the electrical fault, starting the first stator and the second stator.

[0016] In another aspect, the method further includes operating the first stator in at least three phases and operating the second stator in a set of two phases when an electrical fault in the second stator is detected.

[0017] In another aspect, the method further comprises measuring the back electromotive force using the first stator.

[0018] In another aspect, the first stator and the second stator each include a set of three motor windings.

[0019] In another aspect, the method further comprises increasing the axial force and the radial torque relative to a predetermined amount to displace the impeller from the disk within the implantable blood pump.

[0020] In another aspect, the method further comprises alternating a phase angle of the first stator.

[0021] In one aspect, a method of starting an implantable blood pump includes performing a plurality of motor start attempts, the plurality of motor start attempts including applying a first voltage less than a predetermined maximum voltage to a plurality of stators. In response to failure of the plurality of motor start attempts, performing an additional start attempt, the additional start attempt including applying a predetermined maximum voltage to the plurality of stators.

[0022] In another aspect, the multiple motor start attempts include a group of two start attempts.

[0023] In another aspect, the method further comprises detecting whether a motor start has occurred after each of the plurality of motor start attempts.

[0024] In another aspect, the method further comprises gradually increasing the motor speed from the inactive state to the operating speed.

[0025] In another aspect, the predetermined maximum voltage is between 10V-14V.

[0026] The details of one or more aspects of the disclosure are set forth in the following drawings and description. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] A more complete understanding of the present invention and its attendant advantages and features will be more readily appreciated by referring to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0028] Figure 1 depicts an exploded view of an exemplary implantable blood pump;

[0029] Figure 2 Describes the configuration to monitor and control Figure 1 Example control circuit for activation of a motor of an implantable blood pump;

[0030] Figure 3 It is used to control Figure 2 A flowchart of an exemplary starting routine for starting a motor;

[0031] Figure 4 It is depicted with Figure 3 a graph of one or more pump parameters associated with a startup routine;

[0032] Figure 5 It is used to control Figure 2 A flowchart of another exemplary starting routine for starting a motor;

[0033] Figure 6 yes Figure 1 Schematic diagram of an exemplary power supply, pump controller, impeller, and a pair of stators of an implantable blood pump;

[0034] Figure 7 It is used to control Figure 2 A flowchart of another exemplary starting routine for starting a motor; and

[0035] Figure 8 It is depicted with Figure 7 A graph of one or more pump parameters associated with a startup routine. DETAILED DESCRIPTION

[0036] Before describing the exemplary embodiments in detail, it should be noted that the embodiments reside primarily in a combination of apparatus components and process steps related to starting a blood pump. Therefore, system and method components have been represented by conventional symbols in the drawings where appropriate, showing only those specific details that are relevant to understanding the embodiments of the present disclosure so as not to obscure the present disclosure with details that are readily apparent to one of ordinary skill in the art having the benefit of the description herein.

[0037] As used herein, relational terms such as "first" and "second", "top" and "bottom" may be used only to distinguish one entity or element from another entity or element, without requiring or implying any physical or logical relationship or order between such entities or elements. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the concepts described herein. As used herein, the singular forms "one", "an", and "said" are also intended to include plural forms unless the context clearly indicates otherwise. It will be further understood that when used herein, the terms "comprise", "include", "includes", and / or "includes" specify the presence of the features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0038] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art described in the present disclosure. It will be further understood that, unless expressly defined herein, the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant technology, and will not be interpreted in an idealized or overly formal sense.

[0039] In the embodiments described herein, connection terms such as "in communication with" may be used to indicate electrical or data communication, which may be achieved, for example, by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling, or optical signaling. Those skilled in the art will appreciate that the various components may interoperate and that modifications and variations in achieving electrical and data communication are possible.

[0040] It should be understood that the various aspects disclosed herein may be combined in combinations different from those specifically presented in the specification and drawings. It should also be understood that, depending on the example, certain actions or events of any of the processes or methods described herein may be performed in different sequences, may be added, merged, or omitted entirely (e.g., all described actions or events may not be necessary to perform these techniques). In addition, for the purpose of clarity, although certain aspects of the present disclosure are described as being performed by a single module or unit, it should be understood that the techniques of the present disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

[0041] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or codes on a computer-readable medium and executed by a hardware-based processing unit. A computer-readable medium may include a non-transitory computer-readable medium, which corresponds to a tangible medium, such as a data storage medium (e.g., RAM, ROM, EEPROM, flash, or any other medium that can be used to store desired program code in the form of instructions or data structures and can be accessed by a computer).

[0042] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Thus, the term "processor" as used herein may refer to any of the foregoing structures or any other physical structure suitable for implementing the described techniques. Moreover, the techniques may be fully implemented in one or more circuits or logic elements.

[0043] Referring now to the drawings, wherein like reference numerals refer to like elements throughout, Figure 1 An exemplary blood pump constructed according to the principles of the present application is shown in FIG. 1 and is generally designated as “10”. The general arrangement of the blood pump assembly may be similar to that described in U.S. Pat. Nos. 7,997,854 and 8,512,013. The blood pump 10 may be identical or similar to the blood pump 10, the disclosure of which is incorporated herein by reference in its entirety. For example, the blood pump 10 may include a housing 12 having a chamber 14, an inflow cannula 16, and a main longitudinal axis 18 extending through the blood pump. The closed flow path extends along the axis 18 from an upstream direction as indicated by arrows U and D, respectively, to a downstream direction. A generally disc-shaped ferromagnetic impeller 20 is mounted in the chamber 14 between a first ceramic disc 22 and a second ceramic disc 24 for rotation about the axis 18.

[0044] The blood pump 10 can be arranged so that the impeller 20 is suspended within the housing 12 by a non-contact bearing (e.g., an electromagnetic bearing, a fluid dynamic bearing, or a combination of these two bearings). For example, the blood pump 10 can include a first stator 26 and a second stator 28 disposed within the housing 12. The first stator 26 can be located near the first ceramic disk 22, and the second stator 28 can be located near the second ceramic disk 24. In operation, a voltage can be applied to one or more coils of the first stator 26 and / or the second stator 28 to rotate the impeller 20 to propel blood. Figure 2 As shown, the electrical connector 30 can supply voltage to the coil from a power source 32 coupled to or stored within the controller 34, such as an external AC power source, an external battery, an implanted battery, or any combination thereof.

[0045] refer to Figure 1 and 2 , the first stator 26 and the second stator 28 can operate in combination or independently of each other, and can each form part of a sensorless three-phase brushless direct current ("BLDC") motor 36. In one configuration, the coils of the first stator 26 and the second stator 28 are in the form of three motor windings, which are controlled by different phases U, V, and W of the power input for three-phase motor control. The BLDC motor includes an inverter circuit for converting the DC input to a three-phase output. Alternatively, the blood pump 10 can receive an alternating current (AC) three-phase input. Examples of three-phase motor control methods and devices are provided in co-owned and co-pending U.S. applications Nos. 62 / 271,278 and 15 / 710323, the disclosures of which are incorporated herein by reference in their entirety.

[0046] Figure 2 An example control circuit 38 is shown coupled to the blood pump 10, the control circuit including hardware and software for monitoring and controlling the startup and subsequent operation of one or both of the stators 26 and 28 according to the routines of the present disclosure. The control circuit 38 includes a processor 42, a memory 44, and an interface 46 for interfacing with the motor 36. The memory 44 stores information accessible by the processor 42, including instructions 48 that can be executed by the processor 42. The memory 44 also includes data 50 that can be retrieved, manipulated, or stored by the processor 42. Additional details associated with the control circuit 38 are provided in commonly owned and co-pending U.S. Application No. 15 / 710,323, the disclosure of which is incorporated herein by reference in its entirety.

[0047] In accordance with the present disclosure, the instructions 48 stored in the memory 44 may include one or more instruction sets or modules for performing certain operations. One such module may be a motor control module 52 for controlling the operation of the motor 36 (e.g., increasing or decreasing the current supplied to the motor). The instructions may also include one or more motor monitoring modules 54 for monitoring the operation of the motor 36. Examples of motor control and monitoring modules may be found in any of the commonly owned and co-pending U.S. applications Ser. Nos. 13 / 355,297, 13 / 951,302, 14 / 294,448, 14 / 950,467, 62 / 266,871, and 62 / 271,618, the disclosures of which are incorporated herein by reference in their entirety.

[0048] Reference now Figure 3 , the startup routine 56 may be performed by Figure 2 , or by a control circuit having similar capabilities coupled to the controller 34. The startup routine 56 generates a relatively high amount of initial torque compared to the torque that may be generated during one or more alternative startup routines. Thus, the startup routine 56 may be activated after another startup routine fails, and thus may be referred to as an auxiliary startup routine. The startup routine disclosed herein is configured to shift the impeller 20 from a stationary starting position (in which the impeller 20 is in contact with the first disk 22 and / or the second disk 24) to an operating position (in which the impeller 20 is suspended within the housing 12 to propel blood).

[0049] In one configuration, the startup routine 56 begins at step 58, where the control circuit 38 instructs the motor 36 to gradually increase the motor speed from an inactive state (including a speed of zero when the impeller 20 is stationary) to an operating speed during a ramp-up phase. During the speed increase, at step 60, the control circuit 38 applies a predetermined maximum voltage, thereby generating a high torque to overcome friction or clotted blood that may impede movement of the impeller 20. At step 62, the control circuit 38 transitions or switches from the gradual increase in motor speed to closed-loop speed control to achieve an operating speed at which the blood pump operates in a normal mode. The closed-loop speed control may be performed by the control circuit 38 of the controller ( Figure 2 ) is performed. For example, the motor speed can be maintained by adjusting the voltage according to the speed difference generated by the torque.

[0050] In response to the predetermined maximum voltage still being applied, the transition to closed loop control may cause an overshoot of the motor speed, where the motor speed increases from the first speed to an overshoot speed that is greater than the operating speed. In other words, rather than the control loop increasing directly to the operating speed from the inactive state, an overshoot of the operating speed may occur unintentionally. This overshoot may be minimized by appropriately adjusting the closed loop speed control parameters.

[0051] refer to Figure 4 , a speed waveform "SP" is depicted in solid lines, which illustrates that the motor speed gradually increases from an initial speed 64 of zero in an inactive state to a first speed 66. The first speed 66 may be between 250 RPM and 600 RPM, such as 480 RPM, or otherwise pre-programmed according to pump parameters. The term "gradually" encompasses speed changes that occur within a first time period 68, such as 2 seconds to 3 seconds. During the first time period 68, the speed waveform is generated as a non-linear frequency ramp. The control circuit 38 may include a timer or timing mechanism configured to control the timed changes in the motor speed.

[0052] In one configuration, a predetermined maximum voltage is applied during the ramp-up phase of the start-up routine 56. The predetermined maximum voltage has a corresponding torque output that is relatively high compared to the amount of torque present in other phases of motor start-up. For example, as depicted by the voltage / current waveform "VC" represented by a solid line, during the first time period 68 starting from the initial activation, the voltage increases from zero to a predetermined maximum voltage. The predetermined maximum voltage can be between 10V and 14V, and the first time period 68 can be less than one second. The controller 34 can be programmed to maintain the voltage below a predetermined maximum voltage threshold, such as 14V, or otherwise specified. The increase in motor speed can result in a speed phase that follows directly after the ramp-up phase, thereby bypassing the commutation phase. In other words, the start-up routine 56 is performed without incrementally ramping the motor voltage and searching or measuring the back electromotive force (i.e., "BEMF" or "back-EMF") signal indicating impeller movement or positioning, as usually found in the commutation phase. The speed phase may include an overshoot and may occur within a second time period 72 that is less than the first time period 68, such as less than one second, such as between 0.25 seconds and 0.75 seconds. In other words, the motor speed increases at a faster rate during the speed phase than during the ramp-up phase. When the motor 36 reaches an operating speed 74, such as between 1800 RPM and 4000 RPM, normal operation of the motor 36 may begin. In general, the ramp-up phase and the speed phase, which include the transition of the motor speed from an initial speed of zero to the operating speed 74, occur within a startup duration of less than 8 seconds, such as between 3-4 seconds.

[0053] refer to Figure 5, the control circuit 38 or a control circuit with similar capabilities coupled to the controller 34 performs a startup routine 76, which includes detecting an electrical fault in the first stator 26 or the second stator 28. The startup routine 76 may be referred to as a 5-wire startup. For example, in one configuration, the startup routine 76 begins at step 78, where an electrical fault is detected, for example, in the second stator 28 using the control circuit 38. At step 80, in response to the electrical fault condition, the startup of the first stator 26 and the second stator 28 is initiated, for example, by applying a voltage from a power supply to the first stator 26 and the second stator 28. In other words, both stators are started despite the electrical fault condition. At step 82, closed-loop control of the motor may be initiated, the control including using a non-faulty stator for monitoring the BEMF. In another configuration, the electrical fault may be detected after the startup is complete, for example, when the stator is running at an operating speed in a normal operating mode. The detection of an electrical fault in the second stator 28 is provided for illustrative purposes only, as the electrical fault condition may exist in either stator.

[0054] refer to Figure 6 , depicts additional details associated with the startup routine 76, including the power source 32 and the controller 34 in communication with the first stator 26 having three motor windings 84 and the second stator 28 having three motor windings 86 on the opposite side of the impeller 20. The controller 34 initiates startup of the first stator 26 by driving the three motor windings 84 using voltage and current from the power source 32 so that the first stator 26 operates in three phases (e.g., U, V, W). Initiating startup of the first stator 26 generates a predetermined amount of axial force and radial torque for rotating and suspending the impeller 20.

[0055] As mentioned above, before starting the first stator 26 and the second stator 28, the controller 34 can detect an electrical fault condition, such as a continuity loss 88 in one or more of the motor windings 86 of the second stator 28. Despite the electrical fault condition, the controller 34 can still initiate the startup of the second stator 28 so that the second stator 28 operates in a set of two phases, thereby providing a five-wire startup between the combined stators 26, 28. Compared with the axial force and radial torque generated using only a single stator, even in the presence of an electrical fault condition, starting the startup of the second stator 28 also generates a greater amount of axial force and radial torque to increase the likelihood of a successful start. A successful startup includes the impeller 20 being rotated and suspended within the housing 12 to propel blood in a normal operating mode. In the event that an electrical fault is detected in either stator after the startup is completed, the first stator 26 and the second stator 28 can be configured to continue to operate at an operating speed in a normal operating mode despite the electrical fault condition.

[0056] The two operating phases of the second stator 28 or the faulty stator can be changed according to the position of the continuity loss 88 relative to the coil in an effort to rotate and suspend the impeller 20. In other words, the phase angle of the first stator 26 and / or the second stator 28 relative to the housing 12 can be changed according to the position of the faulty stator within the housing 12 (e.g., near the first disk 22 or the second disk 24) and the location of the electrical fault condition. For example, the control circuit 38 can change the line phase of the first stator 26 and / or the second stator 28 to change the phase angle and change the torque in an effort to rotate the impeller 20.

[0057] Reference now Figure 7 , the control circuit 38, or a control circuit of similar capability coupled to the controller 34, performs a start-up routine 90 in which a first voltage less than a predetermined maximum voltage is applied to the stators 26, 28. In one configuration, the predetermined maximum voltage is a predetermined maximum voltage that is lower than the predetermined maximum voltage discussed above with respect to the start-up routine 56. Thus, the start-up routine 90 attempts motor starting using an amount of torque that is less than that initially produced during the start-up routine 56 in an attempt to reduce the risk of injury to the patient that may result from the higher amount of torque. Thus, the start-up routine 90 may be referred to as a primary start-up routine, while the start-up routine 56 is a secondary start-up routine.

[0058] In one configuration, the start routine 90 begins at step 92 with a first motor start attempt, which includes, for example, applying a first voltage to both stators 26, 28 from the power supply 32. If unsuccessful, the control circuit 38 performs a second start attempt in the manner described with respect to the first start attempt. In one configuration, the interval between performing the two start attempts is 2 seconds to 3 seconds; however, other configurations may include a single start attempt and / or more than two start attempts with shorter or longer intervals between the two or more start attempts.

[0059] At step 94, after each motor start attempt, the control circuit 38 detects whether the motor 36 is successfully started. In response to a failure of the motor start attempt, at step 96, the control circuit 38 performs an additional start attempt using the start routine 56. In other words, the additional start attempt includes applying a predetermined maximum voltage greater than the first voltage to the stators 26, 28 and implementing the speed ramp of the start routine 56.

[0060] For example, refer to Figure 8, the first and second motor start attempts include applying a first voltage depicted using a voltage-current waveform "VC2" to the first stator 26 and / or the second stator 28 during a first time period. In one configuration, the first voltage is between 8V and 12V, and the first time period includes the first stator 26 and the second stator 28 being in an inactive state. The first voltage and the predetermined maximum voltage may be stored in a memory of the controller 34.

[0061] If the start attempt is successful, during the ramp-up phase, the first voltage may increase from zero to a range below the predetermined maximum voltage threshold in less than one second. In addition, the motor speed depicted using the speed waveform "SP2" shown as a solid line will undergo a step change in the ramp-up phase, the commutation phase, and the speed phase that may exceed a start duration of more than 10 seconds. Whether the start is successful may be determined by one or more methods, such as the control circuit 38 attempting to search for and / or measure a BEMF signal indicating the motion or position of the impeller 20.

[0062] If the start attempt (e.g., two start attempts) fails to successfully start the motor 36 and fails to displace the impeller 20 from the disks 22, 24, an additional start attempt will be performed. In one configuration, the additional start attempt is a start routine 56 that includes applying a predetermined maximum voltage (e.g., 14V) to the first stator 26 and / or the second stator 28 from an inactive state and transitioning the motor speed from the ramp-up phase directly to the speed phase to exclude the commutation phase. In other configurations, an alternative amount of voltage may be used during another type of start routine.

[0063] Certain embodiments of the invention include:

[0064] Embodiment 1. A method for starting an implantable blood pump, comprising:

[0065] gradually increasing the motor speed from an inactive state to a first speed during a first time period;

[0066] applying a predetermined maximum voltage during said gradual increase in said motor speed; and

[0067] A transition is made from the gradual increase in the motor speed to closed loop speed control to achieve an operating speed, the operating speed being greater than the first speed.

[0068] Embodiment 2. The method of embodiment 1, further comprising bypassing a commutation phase.

[0069] Embodiment 3. The method of embodiment 1, further comprising maintaining the voltage below a predetermined maximum voltage threshold.

[0070] Embodiment 4. A method according to embodiment 3, wherein the transition of the motor speed from the inactive state to the operating speed occurs within a startup duration of less than 8 seconds.

[0071] Embodiment 5. The method of embodiment 4 further comprising moving an impeller of the blood pump from a starting position in which the impeller contacts the disk to an operating position in which the impeller is moved away from the disk.

[0072] Embodiment 6. The method of embodiment 1 further comprising generating a non-linear frequency ramp when gradually increasing the motor speed from the inactive state to the first speed.

[0073] Embodiment 7. The method of Embodiment 1, further comprising applying a predetermined maximum voltage to a plurality of coils of a stator disposed within the implantable blood pump when gradually increasing the motor speed from the inactive state to the first speed.

[0074] Embodiment 8. The method of claim 1 wherein the inactive state comprises a speed of zero, and the first speed is between 100 RPM and 2000 RPM.

[0075] Embodiment 9. The method of embodiment 1, wherein the first time period is between 2 seconds and 3 seconds, and the second time period is less than one second.

[0076] Embodiment 10. A method of starting an implantable blood pump comprising a first stator and a second stator, the method comprising:

[0077] detecting an electrical fault in one of the group consisting of the first stator and the second stator; and

[0078] In response to the electrical fault, starting of the first stator and the second stator is initiated.

[0079] Embodiment 11. The method of embodiment 10, further comprising operating the first stator in at least three phases and operating the second stator in a set of two phases when an electrical fault in the second stator is detected.

[0080] Embodiment 12. The method of embodiment 11, further comprising measuring back EMF using the first stator.

[0081] Embodiment 13. The method of claim 10 wherein the first stator and the second stator each comprise a set of three motor windings.

[0082] Embodiment 14. The method of Embodiment 10, further comprising increasing the axial force and radial torque relative to a predetermined amount to displace an impeller from a disk within the implantable blood pump.

[0083] Embodiment 15. The method of embodiment 10, further comprising alternating a phase angle of the first stator.

[0084] Embodiment 16. A method for activating an implantable blood pump, comprising:

[0085] performing a plurality of motor starting attempts, the attempts comprising applying a first voltage less than a predetermined maximum voltage to a plurality of stators; and

[0086] In response to failure of the plurality of motor starting attempts, additional starting attempts are performed, the additional starting attempts comprising applying a predetermined maximum voltage to the plurality of stators.

[0087] Embodiment 17. The method of Embodiment 16, wherein the plurality of motor start attempts comprises a group of two start attempts.

[0088] Embodiment 18. The method of embodiment 16 further comprising detecting whether a motor start has occurred after each of the plurality of motor start attempts.

[0089] Embodiment 19. The method of Embodiment 16, further comprising gradually increasing the motor speed from an inactive state to an operating speed.

[0090] Those skilled in the art will appreciate that the present invention is not limited to what has been specifically shown and described above. In addition, unless otherwise mentioned above, it should be noted that all drawings are not drawn to scale. Based on the above teachings, various modifications and variations can be made without departing from the scope and spirit of the present invention, and the scope and spirit of the present invention are limited only by the appended claims.

Claims

1. A system for activating an implantable blood pump, comprising: case; an impeller located in the housing; an electric motor configured to drive the impeller; and The control circuit, whose processing circuit includes one or more processors, is configured to: gradually increasing the motor speed from an inactive state to a first speed during a first time period; applying a predetermined maximum voltage during said gradual increase in said motor speed; transitioning from said gradual increase in motor speed to closed loop speed control to operate said motor at an operating speed; and wherein the transition to closed loop speed control causes an overshoot of the motor speed in response to the predetermined maximum voltage being applied during the transition, wherein the motor speed increases from the first speed to an overshoot speed greater than the operating speed.

2. The system according to claim 1, wherein: The processing circuit is configured to minimize the overshoot by adjusting a closed-loop speed control parameter.

3. The system according to claim 1, wherein: The control circuit is configured to maintain the voltage below a predetermined maximum voltage threshold.

4. The system according to claim 1, wherein: The control circuit is configured to generate a non-linear frequency ramp when gradually increasing the motor speed from the inactive state to the first speed.

5. The system according to claim 1, wherein: The inactive state includes a speed of zero, and the first speed is between 250 RPM and 600 RPM.

6. The system according to claim 1, wherein: The operating speed is between 1800RPM and 4000RPM.

7. The system according to claim 1, wherein: The first time period is between 2 seconds and 3 seconds.

8. The system according to claim 1, wherein: The transition occurs during a second time period of less than one second.

9. The system according to claim 1, wherein: The duration from the inactive state to the operating speed occurs within a startup duration of less than 8 seconds.

10. The system of claim 1, further comprising: The stator is arranged in the housing and has a plurality of coils. Wherein, when gradually increasing the motor speed from the inactive state to the first speed, the control circuit is configured to apply the predetermined maximum voltage to the plurality of coils.

11. The system according to claim 1, wherein: The control circuit is configured to maintain the operating speed by adjusting a voltage according to a speed difference generated by a torque.

12. The system of claim 1, wherein: The control circuit is configured to increase the motor speed at a faster rate during the transition period than during the gradual increase in motor speed.

13. The system of claim 1, wherein: The predetermined maximum voltage is between 10V and 14V.

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