JP4252197B2 - Blood pump device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blood pump device, and more particularly to a magnetic levitation blood pump device that magnetically levitates an impeller and discharges blood.
[0002]
[Prior art]
FIG. 7 is a longitudinal sectional view of a conventional magnetic levitation blood pump apparatus and a diagram showing a controller. In FIG. 7, the magnetic levitation blood pump apparatus 100 is configured such that an electromagnet part 120, a pump part 130, and a motor part 140 are built in a casing 101 in the axial direction. An electromagnet 121 and a magnetic bearing sensor 122 are built in the electromagnet portion 120. An inflow port 102 through which blood flows is formed in the center of one side surface of the casing 101 in the axial direction, and at least three electromagnets 121 and magnetic bearing sensors 122 are arranged around the inflow port 102 at predetermined intervals. Has been. The electromagnet 121 and the magnetic bearing sensor 122 are attached to a partition wall 103 that partitions the electromagnet portion 120 and the pump portion 130.
[0003]
An impeller (impeller) 131 is rotatably accommodated in the pump unit 130, and the electromagnet unit 120 side (one side) of the impeller 131 is supported in a non-contact manner by the electromagnet 121 through the partition wall 103. A distance from one side of the impeller 131 is detected by the sensor 122. A permanent magnet 132 is embedded on the other side of the impeller 131. The motor unit 140 houses a motor 141 and a rotor 142. A permanent magnet 143 is embedded on the surface of the rotor 142 facing the pump unit 130 so as to face the permanent magnet 132 embedded in the impeller 131 via the partition wall 104.
[0004]
In the blood pump apparatus configured as described above, the sensor output of the magnetic bearing sensor 122 is given to a sensor circuit (not shown) included in the controller 150, and one side of the impeller 131 and the magnetic bearing sensor 122 are transmitted by the sensor circuit. The distance between is detected. The output of the sensor circuit is given to a PID compensator (not shown) to perform PID compensation, and the output of the PID compensator is amplified by a power amplifier (not shown) and given to the electromagnet 121. Therefore, the attraction force to the opposing surface of the impeller 131 is controlled by the electromagnet 121.
[0005]
On the other hand, an attraction force composed of permanent magnets 132 and 143 acts on the motor unit 140 side of the impeller 131, and the impeller 131 is magnetized by a non-control type bearing by the permanent magnets 132 and 143 and a control type bearing by the electromagnet 121. The blood floats and rotates by the driving force of the motor 141 controlled by the controller 150, and the blood that has flowed into the inflow port 102 flows out from a discharge port (not shown) formed in the pump unit 130.
[0006]
[Problems to be solved by the invention]
The magnetic levitation blood pump device 100 shown in FIG. 7 is used as a blood pump device for an artificial heart. The controller 150 can switch the motor 141 between a constant rotation mode and a constant motor current mode. The constant rotation mode is a mode in which the rotation speed of the motor is kept constant even when the load changes when rotating at a rotation speed of 2000 rpm, for example. It is a mode that keeps on. In the blood pump device, in the motor current constant mode, if the blood vessel contracts, the rotation speed increases because it tries to supply a constant amount of blood, and when the blood vessel expands, the load decreases, so the rotation speed slows down. .
[0007]
However, in the magnetically levitated blood pump device, if the power supply voltage fluctuates even in the constant motor current mode, the power supply voltage fluctuates, for example, as the power supply voltage rises, as shown in FIG. As a result, the rotational speed also varies. As a power source for the blood pump device, a DC voltage obtained by rectifying a commercial AC voltage into a DC voltage and a DC voltage from a battery are switched and supplied. Although the rated voltage of the rectified DC voltage is output by a stabilization circuit or the like, the battery outputs a higher voltage, for example, 15 V when fully charged even if the rated voltage is 12 V. When switching to the DC voltage of the battery, the rotational speed of the magnetically levitated blood pump device changes significantly, which may cause an overload to the pump load system and cause trouble.
[0008]
Therefore, a main object of the present invention is to provide a blood pump device that can reduce the change in the rotational speed even if the power supply voltage fluctuates in the constant motor current mode.
[0009]
[Means for Solving the Problems]
Blood pump apparatus according to the present invention, having a rotating member in a casing, a pump unit for discharging the rotating body of the rotating the thus blood, a support for supporting a rotating body, a motor for rotating the rotary member And a controller that is driven by the power supply voltage, supplies current to the motor unit according to the motor current command value, and rotates the motor unit . The controller receives the power supply voltage and the motor current command value, and varies the power supply voltage. The motor value command unit that adjusts the motor current command value according to the fluctuation of the power supply voltage and the motor current command value that is driven by the power supply voltage and adjusted by the command value adjustment unit so that the rotation speed of the motor unit does not change due to And a current supply unit for supplying a current to the motor unit . Therefore, troubles due to fluctuations in the power supply voltage can be prevented beforehand.
[0011]
Preferably, the further selection and AC / DC converter for converting an ac voltage to a first DC voltage, a battery for outputting a second DC voltage, the first or the second DC voltage, and selected And a switching circuit that supplies the controller with the first or second DC voltage as a power supply voltage .
[0012]
Also preferably, further, the AC / DC converter for converting an ac voltage to a first DC voltage, a battery for outputting a second DC voltage, and switching circuit for selecting the first or the second DC voltage And a DC / DC converter that converts the first or second DC voltage selected by the switching circuit into a third DC voltage and supplies the third DC voltage as a power supply voltage to the controller. To do.
[0013]
Preferably , the support unit is coupled to the rotating body in a non-contact manner by a magnetic force, and further , a position detection unit for detecting the floating position of the rotating body, and the rotation body is supported in a non-contact manner based on the detection result of the position detection unit. And a controllable magnetic bearing.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a view showing a blood pump device according to an embodiment of the present invention. In particular, FIG. 1 (a) shows a longitudinal sectional view, and FIG. 1 (b) shows a line AA in FIG. 1 (a). It is sectional drawing which follows. 2 is a cross-sectional view taken along line BB in FIG. 1A, and FIG. 3 is a cross-sectional view taken along CC in FIG. Here, the sensor is not shown in FIG.
[0015]
In FIG. 1, in the blood pump apparatus, a casing 1 is divided in an axial direction by partition walls 11, 12, 13, and 14, and a magnetic bearing portion 20, a pump portion 30, and a motor portion 40 are provided in each section. The casing 1 is made of plastic, ceramic, metal or the like, but the partition 12 between the magnetic bearing part 20 and the pump part 30 and the partition 13 between the pump part 30 and the motor part 40 in the casing 1 are magnetic. Since the material cannot be used, it is composed of a non-magnetic material.
[0016]
A pump chamber 33 is provided in the casing 1 of the pump unit 30, and the impeller 31 rotates in the pump chamber 33, and the blood flowing in from the inlet 15 is discharged from the outlet 16 shown in FIG. To do. The impeller 31 has a plurality of blades 34, and the blades 34 are formed in a spiral shape as shown in FIG. The impeller 31 includes a nonmagnetic member 35 having a permanent magnet 32 constituting a non-control type magnetic bearing, and a soft magnetic member 36 corresponding to a rotor of the control type magnetic bearing. The permanent magnet 32 is divided in the circumferential direction of the impeller 31, and magnets adjacent to each other are magnetized by magnetic poles in opposite directions.
[0017]
In addition, by coating heparin which is an anticoagulant in the entire pump chamber 33, thrombus formation at these portions can be prevented, and the pump chamber 33 can be used as a blood transport pump. In this case, the heparin coating provides effects such as coagulation activation inhibition, platelet protection, activation inhibition, inflammatory activity inhibition, and fibrinolytic activation inhibition.
[0018]
Further, in FIG. 1, the nonmagnetic member 35 of the impeller 31 is indicated by oblique lines, the soft magnetic member 36 is indicated by spots, and the other portions indicate nonmagnetic materials. When used in applications that transport corrosive fluids such as blood, the soft magnetic material is highly corrosion resistant ferritic stainless steel (SUS447J, SUS444, etc.), and the nonmagnetic material is high corrosion resistance austenitic stainless steel (SUS316L, etc.). Or a titanium alloy, pure titanium, or the like.
[0019]
A cylindrical portion 48 extending from the center of the partition wall 13 toward the partition wall 14 is formed in the motor unit 40 so as to face the side of the impeller 31 having the permanent magnet 32. A motor bearing 49 formed of a rolling bearing is provided on the outer peripheral surface of the cylindrical portion 48, and a motor rotor 46 is rotatably supported by the motor bearing 49. A motor stator 47 is provided at the tip of the cylindrical portion 48. Is installed. The motor rotor 46 is driven by a motor stator 47 and rotates. The motor rotor 46 is provided with the same number of permanent magnets 45 as the impeller 31 so as to face the permanent magnets 32 of the impeller 31 and to exert an attractive force. The permanent magnets 45 are also magnetized adjacent to each other in opposite magnetic poles.
[0020]
As the motor, a synchronous motor including a DC brushless motor, an asynchronous motor including an induction motor, or the like is used, but the type of motor is not limited.
[0021]
The electromagnet unit 20 and the magnetic bearing sensor 24 are attached to the electromagnet unit 20 on the inner wall of the partition wall 12 that partitions the electromagnet unit 20 and the pump unit 30 so as to face the side having the soft magnetic member 36 of the impeller 31. . The impeller 31 can be held in the center of the pump chamber 33 by the electromagnet 23 and the magnetic bearing sensor 24 in balance with the attractive force of the permanent magnets 32 and 45 in the pump chamber 33.
[0022]
With this configuration, the heat generated by the electromagnet 23 can be transmitted to the partition wall 12 and cooled by the blood in the pump unit 30. Similarly, heat generated in the motor stator 47 is also transmitted from the cylindrical portion 48 to the partition wall 13 and is cooled by the blood in the motor portion 30. As a result, heat transfer to the outside of the casing 1 can be reduced. In addition, heat transmitted to the magnetic bearing sensor 24 can be reduced, and sensing can be stabilized. Further, if the thicknesses of the partition walls 12 and 13 are increased to some extent to give the strength enough to attach the electromagnet 23, the magnetic bearing sensor 24, and the motor stator 47, the thickness of the outer diameter portion of the housing 1 can be reduced. .
[0023]
The electromagnet 23 and the magnetic bearing sensor 24 are arranged as shown in FIGS. That is, the sensor 241 is disposed between the magnetic poles 51 and 52 of the electromagnets 23 that form a pair, the sensor 242 is disposed between the magnetic poles 53 and 54, and the sensor 243 is disposed between the magnetic poles 55 and 56. Is arranged. As these sensors 241 to 243, magnetic sensors such as a reluctance sensor are used.
[0024]
Further, as shown in FIG. 3, the yokes 71 to 76 of each electromagnet 23 are formed in a columnar shape, and electromagnet coils 81 to 86 are wound around the electromagnet yokes 71 to 76, respectively.
[0025]
Thus, by arranging the magnetic poles 51 to 56 in the circumferential direction, the storage space for the electromagnetic coils 81 to 86 that can be stored in the magnetic bearing portion 40 can be increased, and the coil winding space can be increased without increasing the pump size. Can be secured widely. By expanding the coil storage space in this way, it is possible to increase the number of turns of the electromagnet coil and increase the wire diameter of the coil. As a result, power saving of the electromagnet can be achieved.
[0026]
Further, by making the shape of the electromagnet yokes 71 to 76 cylindrical, the winding operation of the electromagnet coils 81 to 86 around the electromagnet yokes 71 to 76 is facilitated. Furthermore, since the shapes of the electromagnet yokes 71 to 76 are simple, insulation from the electromagnet coils 81 to 86 is ensured. Although the electromagnet yokes 71 to 76 are cylindrical, this may be a prism, which facilitates the coil winding operation, and as a result, it is easy to ensure the insulation withstand voltage between the coil and the yoke. .
[0027]
Further, in FIG. 2 and FIG. 3, all the electromagnetic yokes 71 to 76 and the electromagnetic coils 81 to 86 are arranged on the same circumference, but in order to effectively secure a storage space, each of the electromagnetic yokes 71 to 76 and The electromagnet coils 81 to 86 may not be on the same circumference.
[0028]
By arranging the magnetic poles and yokes of each electromagnet of the magnetic bearing in the circumferential direction, it becomes possible to increase the space of the magnetic bearing portion, that is, to make the yoke of the electromagnet a cylinder or a prism, and the coil winding work can be reduced. As a result, the withstand voltage between the coil and the yoke is easily secured.
[0029]
FIG. 4 is a block diagram showing an example of a controller for controlling the blood pump device of one embodiment of the present invention, and FIGS. 5 and 6 are diagrams showing a power supply circuit for supplying a power supply voltage to the power amplifier shown in FIG. It is.
[0030]
The blood pump device to which the present invention is applied normally rotates within a range of 1500 rpm to 2500 rpm, and rarely rotates at a speed higher than or lower than that. Therefore, in the embodiment of the present invention, by calculating the relationship between the current and the motor current command value between a certain number of rotations, the motor current command value can be rotated at the same number of rotations even if the power supply voltage fluctuates. To control. Such a control is realized by the controller 50 shown in FIG.
[0031]
In FIG. 4, the controller 50 includes a motor control circuit 51, a power amplifier 52, an operational amplifier OP1, and resistors R1, R2, and R3. The power amplifier 52 drives the motor unit 40 shown in FIG. 1 and supplies a predetermined DC current to the motor stator 47 in accordance with a control signal given from the motor control circuit 51.
[0032]
A DC voltage is supplied to the power amplifier 52 from the power supply circuit shown in FIG. In the example shown in FIG. 5, a commercial AC voltage is converted into a DC voltage by an AC / DC power supply 61, and more preferably, a stabilized DC voltage is output. This DC voltage is applied to the contact a of the switch 63, A DC voltage from the battery 62 is applied to the contact b of the switch 63. Then, by switching the switch 63, a DC voltage is output from the contact c and supplied to the power amplifier 52.
[0033]
In the example shown in FIG. 6, the direct current voltage output from the AC / DC power supply 61 and the direct current voltage from the battery 62 are switched by the switch 63, and further the direct current voltage is applied by the DC / DC power supply 64 such as an inverter power supply. The voltage is stepped up or stepped down and supplied to the power amplifier 52. Even when such a DC / DC power supply 64 is used, it is conceivable that the DC voltage output when the charging voltage of the battery 62 fluctuates also fluctuates.
[0034]
The motor current command value is input to the non-inverting terminal of the operational amplifier OP1, and a DC voltage is applied to the inverting terminal via the resistor R1. Further, a feedback signal is supplied from the power amplifier 52 via the resistor R2 to the inverting terminal of the operational amplifier OP1, and an output signal of the operational amplifier OP1 is supplied via the resistor R3. The output signal of the operational amplifier OP1 is given to the motor control circuit 51.
[0035]
Next, a specific operation of one embodiment of the present invention will be described. For example, a DC 12V voltage is supplied from the AC / DC power supply 61 shown in FIG. 5 to the power amplifier 52, the motor current command value is set to 1A, and the motor rotates at a rotational speed of 1500 rpm. And
[0036]
Here, when the switch 63 switches to the DC voltage from the battery 62 and the battery 62 is fully charged and the DC voltage is, for example, 15V, the power amplifier 52 acts to increase the rotational speed of the motor. However, since the DC voltage is input to the inverting terminal of the operational amplifier OP1 via the resistor R1, the operational amplifier OP1 increases its potential at the inverting terminal as the DC voltage increases from 12V to 15V. It acts to lower the level of the motor current command value that is a signal. Since the motor control circuit 51 controls the rotation of the motor based on the motor current command value, the number of rotations of the motor also decreases.
[0037]
On the other hand, when the DC voltage becomes lower than the rated voltage, if the motor current command value is constant, the rotational speed of the motor decreases. However, since the potential at the inverting terminal of the operational amplifier OP1 also decreases, the operational amplifier OP1 acts to increase the level of its output signal. As a result, the output signal level of the operational amplifier OP1 becomes larger than the motor current command value, and the motor control circuit 51 increases the rotational speed of the motor based on the motor command value.
[0038]
Therefore, according to this embodiment, even if the DC voltage rises or falls below the rated voltage, the motor current command value is lowered or raised so as to reduce fluctuations in the motor rotation speed due to fluctuations in the DC voltage. it can.
[0039]
In the above-described embodiment, the example in which the present invention is applied to the magnetic levitation blood pump apparatus has been described. However, the present invention is not limited to this, and the number of rotations of the motor is controlled to be constant according to the motor current command value. The present invention can be applied to any blood pump device.
[0040]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0041]
【The invention's effect】
As described above, according to the present invention, by supplying a constant current to the rotation drive unit, in the constant current control mode for rotating the rotating body, even if the power supply voltage fluctuates, the fluctuation of the rotation speed is eliminated. By controlling, troubles such as overloading the pump load system can be prevented.
[0042]
More preferably, the rotational speed is made constant by adjusting the motor current command value in accordance with the fluctuation of the power supply voltage.
[Brief description of the drawings]
1A and 1B are views showing an embodiment of the present invention, in which FIG. 1A is a longitudinal sectional view, and FIG. 1B is a sectional view taken along line AA in FIG.
FIG. 2 is a sectional view taken along line BB in FIG.
FIG. 3 is a cross-sectional view taken along line CC in FIG.
FIG. 4 is a schematic block diagram of a controller for controlling the blood pump device of the present invention.
5 is a diagram illustrating an example of a power supply device that supplies a DC power to the power amplifier illustrated in FIG. 4;
6 is a diagram showing another example of a power supply device that supplies a DC power to the power amplifier shown in FIG. 4;
FIG. 7 is a cross-sectional view of a conventional magnetic levitation blood pump apparatus and a controller.
8 is a diagram showing the relationship between the power supply voltage of the motor unit shown in FIG. 7 and the motor rotation speed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Casing, 11, 12, 13, 14 Partition, 15 Inflow port, 16 Discharge port, 20 Electromagnet part, 23 Electromagnet, 24 Magnetic bearing sensor, 30 Pump part, 31 Impeller, 32, 45 Permanent magnet, 33 Pump chamber, 34 blade, 35 non-magnetic member, 36 soft magnetic member, 40 motor part, 47 motor stator, 46 motor rotor, 48 cylindrical part, 49 motor bearing, 50 controller, 51 motor control circuit, 52 power amplifier, 61 AC / DC power supply, 62 battery, 63 selector switch, 64 DC / DC power supply.

Claims (4)

Has a rotating body in a casing, a pump unit for discharging the rotary member of the rotary to the result the blood,
A support portion for supporting the rotating body;
A motor unit for rotationally driving the rotating body ;
A controller driven by a power supply voltage, supplying a current to the motor unit according to a motor current command value, and rotating the motor unit ;
The controller is
A command value adjustment unit that receives the power supply voltage and the motor current command value and adjusts the motor current command value according to the fluctuation of the power supply voltage so that the rotation speed of the motor unit does not change due to the fluctuation of the power supply voltage. When,
A blood pump device comprising: a current supply unit that is driven by the power supply voltage and supplies current to the motor unit according to the motor current command value adjusted by the command value adjustment unit . And an AC / DC converter that converts the AC voltage into a first DC voltage;
A battery that outputs a second DC voltage ;
2. The switching circuit according to claim 1, further comprising: a switching circuit that selects the first or second DC voltage and supplies the selected first or second DC voltage to the controller as the power source voltage. Blood pump device. And an AC / DC converter that converts the AC voltage into a first DC voltage;
A battery that outputs a second DC voltage ;
A switching circuit for selecting the first or second DC voltage;
A DC / DC converter that converts the first or second DC voltage selected by the switching circuit into a third DC voltage, and supplies the third DC voltage to the controller as the power supply voltage; The blood pump device according to claim 1, wherein The support part is coupled to the rotating body in a non-contact manner by a magnetic force ,
Furthermore , a position detection unit that detects the floating position of the rotating body;
The blood pump device according to any one of claims 1 to 3, further comprising a control type magnetic bearing that supports the rotating body in a non-contact manner based on a detection result of the position detection unit. .

Images