Flow estimation using hall-effect sensors for measuring impeller eccentricity
First Claim
1. A blood circulation assist system, comprising:
- a blood pump including an impeller disposed within a blood flow channel of the blood pump and a motor stator operable to magnetically rotate the impeller, the impeller having an impeller axis of rotation around which the impeller is rotated, the motor stator being further operable to magnetically levitate the impeller within the blood flow channel transverse to the impeller axis of rotation;
a controller operatively coupled with the blood pump, the controller being configured to;
determine an impeller rotational speed for the impeller;
determine an amount of a drive current used to rotate the impeller;
determine at least one impeller transverse position parameter, the at least one impeller transverse position parameter being based on at least one of (1) an amount of a bearing current that is used to levitate the impeller transverse to the impeller axis of rotation, and (2) a position of the impeller within the blood flow channel transverse to the impeller axis of rotation;
estimate a flow rate of blood pumped by the blood pump based on the impeller rotational speed and the drive current when the drive current is below a first drive current threshold; and
estimate the flow rate based on the impeller rotational speed and the at least one impeller transverse position parameter when the drive current is above the first drive current threshold.
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Accused Products
Abstract
Methods and apparatus for estimating flow rate in a blood circulation assist system employing impeller eccentricity. A method includes magnetically rotating an impeller within a blood flow channel of a blood pump. The impeller is levitated within the blood flow channel transverse to the impeller axis of rotation. A rotational speed for the impeller is determined. At least one impeller transverse position parameter is determined. The at least one impeller transverse position parameter is based on at least one of (1) an amount of a bearing current that is used to levitate the impeller transverse to the impeller axis of rotation, and (2) a position of the impeller within the blood flow channel transverse to the impeller axis of rotation. A flow rate of blood pumped by the blood pump is estimated based on the impeller rotational speed and the at least one impeller transverse position parameter.
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Citations
22 Claims
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1. A blood circulation assist system, comprising:
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a blood pump including an impeller disposed within a blood flow channel of the blood pump and a motor stator operable to magnetically rotate the impeller, the impeller having an impeller axis of rotation around which the impeller is rotated, the motor stator being further operable to magnetically levitate the impeller within the blood flow channel transverse to the impeller axis of rotation; a controller operatively coupled with the blood pump, the controller being configured to; determine an impeller rotational speed for the impeller; determine an amount of a drive current used to rotate the impeller; determine at least one impeller transverse position parameter, the at least one impeller transverse position parameter being based on at least one of (1) an amount of a bearing current that is used to levitate the impeller transverse to the impeller axis of rotation, and (2) a position of the impeller within the blood flow channel transverse to the impeller axis of rotation; estimate a flow rate of blood pumped by the blood pump based on the impeller rotational speed and the drive current when the drive current is below a first drive current threshold; and estimate the flow rate based on the impeller rotational speed and the at least one impeller transverse position parameter when the drive current is above the first drive current threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for estimating blood flow rate in a blood circulation assist system, the method comprising:
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magnetically rotating an impeller around an impeller axis of rotation within a blood flow channel of a blood pump; magnetically levitating the impeller within the blood flow channel transverse to the impeller axis of rotation; determining, with a controller operatively coupled with the blood pump, an impeller rotational speed for the impeller; determining, with the controller, at least one impeller transverse position parameter, the at least one impeller transverse position parameter being based on at least one of (1) an amount of a bearing current that is used to levitate the impeller transverse to the impeller axis of rotation, and (2) a position of the impeller within the blood flow channel transverse to the impeller axis of rotation; and estimating, with the controller, a flow rate of blood pumped by the blood pump based on the impeller rotational speed and the at least one impeller transverse position parameter. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification