JP5025707B2 - Magnetic levitation pump device - Google Patents

Description

  The present invention relates to a magnetic levitation pump device, and more particularly to a magnetic levitation pump device that discharges a liquid such as blood by rotating an impeller.

  FIG. 7 is a longitudinal sectional view showing the structure of the magnetic levitation pump device of the first conventional example (see, for example, FIG. 7 of Patent Document 1).

  The magnetic levitation pump apparatus shown in FIG. 7 of the present application includes a magnetic levitation pump apparatus main body 1 having a configuration in which an electromagnet 31 for a magnetic bearing and a motor 13 are provided on both sides of an impeller 23, and a controller 200. Yes.

  With reference to FIG. 7, a magnetic levitation pump device of a first conventional example will be described. The magnetically levitated pump apparatus main body 1 of FIG. 7 includes a motor unit 10, a pump unit 20, and a magnetic bearing unit 30 that are sequentially formed in the casing 21 in the axial direction.

  The magnetic bearing unit 30 includes an electromagnet 31 and a magnetic sensor 222 that functions as a position sensor. An inflow port 23c through which liquid flows is formed in the axial center of the casing 21, and at least three electromagnets 31 and magnetic sensors 222 are arranged around the inflow port 23c. The electromagnet 31 and the magnetic sensor 222 are attached to a partition wall 34 that partitions the magnetic bearing portion 30 and the pump portion 20 in the axial direction.

  An impeller 23 (impeller) is rotatably accommodated in the pump chamber 22 in the pump unit 20, and a soft magnetic member 26 is formed on the magnetic bearing unit 30 side (one side) of the impeller 23. ing. One side of the impeller 23 is supported in a non-contact manner by the magnetic bearing electromagnet 31 via the partition wall 34, and a distance from the one side of the impeller 23 is detected by the magnetic sensor 222. A permanent magnet 24 is embedded on the other side of the impeller 23.

  The motor unit 10 houses a motor 13 and a rotor 12 that is a rotating shaft of the motor 13. A permanent magnet 14 is embedded on the surface of the rotor 12 facing the pump unit 20 so as to face the permanent magnet 24 embedded in the impeller 23 via a partition wall 33.

  In FIG. 7, the sensor output of the magnetic sensor 222 is given to the controller 200. FIG. 9 is a block diagram showing the configuration of the controller 200 shown in FIG. The configuration of the controller 200 will be described below with reference to FIG.

  Referring to FIG. 9, sensor output Sa from magnetic sensor 222 included in magnetic levitation pump apparatus main body 1 is input to sensor circuit 223 in controller 200 and converted by internal conversion function f (Sb). Output as sensor circuit output Sb. The sensor circuit output Sb is input to the PID compensator 224, converted by an internal conversion function f (Sp), and output as an electromagnet current command value Sd. The electromagnet current command value Sd is input to the power amplifier 225, and the power amplifier 225 supplies the electromagnet current Im, which is the output thereof, to the magnetic bearing electromagnet 31 in the magnetic levitation pump apparatus main body 1.

  That is, the sensor output Sa of the magnetic sensor 222 is given to a sensor circuit 223 included in the controller 200, and the distance between one side of the impeller 23 and the magnetic sensor 222 is detected by the sensor circuit 223. The sensor circuit output Sb of the sensor circuit 223 is input to the PID compensator 224, and PID compensation is performed. This PID compensation output, that is, the electromagnet current command value Sd is amplified by the power amplifier 225 and is given to the electromagnet 31 as a coil current value. As a result, the attraction force to the opposing surface of the impeller 23 is controlled by the electromagnet 31.

  Referring to FIG. 7 again, the attractive force composed of the permanent magnet 24 and the permanent magnet 14 acts on the motor unit 10 side (the other side) of the impeller 23. That is, the impeller 23 is magnetically levitated by a non-control type bearing composed of the permanent magnet 24 and the permanent magnet 14 and a control type bearing composed of the soft magnetic member 26 and the electromagnet 31 formed on the impeller 23. The impeller 23 is a magnetic cup between a permanent magnet 14 in the rotor 12 rotated by a motor 13 whose driving torque or rotational speed is controlled by a motor controller (not shown) in the controller 200 and a permanent magnet 24 in the impeller 23 facing the impeller 23. A liquid such as blood that is rotationally driven by the ring and flows into the inflow port 23 c is caused to flow out from a discharge port (not shown) formed in the pump unit 20.

  Next, FIG. 8 is a longitudinal sectional view showing the structure of the magnetic levitation pump device of the second conventional example (see, for example, FIG. 3 of Patent Document 2). Referring to FIG. 8, there is shown a magnetic levitation pump device main body 1 in which a motor 13 and an electromagnet 31 are arranged in the same space with respect to an impeller 23, and a controller 200 is not shown.

  With reference to FIG. 8, a magnetic levitation pump device of a second conventional example will be described. The magnetically levitated pump apparatus main body 1 of FIG. 8 includes an actuator unit 40, a pump unit 20, and a casing unit 50 that are sequentially formed in the axial direction. The magnetically levitated pump device main body 1 shown in FIG. 8 has a motor 13 and an electromagnet 31 that are different from the structure of the magnetic levitated pump device main body 1 of the first conventional example shown in FIG. Are different in that they are placed in the same space. With such a structure, the axial length of the outer shape composed of the actuator portion 40, the pump portion 20, and the casing portion 50 (hereinafter referred to as the pump outer axial length) is the first conventional example shown in FIG. The magnetic levitation type pump device main body 1 can be made considerably shorter than the length in the pump outer axial direction. The actuator unit 40 in FIG. 8 includes a motor 13 and an electromagnet 31. A pump chamber 22 is provided in the casing 21 of the pump unit 20, and the impeller 23 rotates in the pump chamber 22.

  In the casing 21, magnetic material cannot be used for the partition wall 35 between the actuator unit 40 and the impeller 23 and the partition wall 36 between the magnetic sensor 222 and the impeller 23. Made of non-magnetic material.

  On the actuator side (left side in FIG. 8) of the impeller 23, a nonmagnetic member 25 having a permanent magnet 24 constituting a non-control type magnetic bearing and a soft magnetic member 26 corresponding to a rotor of the control type magnetic bearing are provided. ing. The permanent magnet 24 is divided in the circumferential direction of the impeller 23, and adjacent magnets are magnetized by magnetic poles in opposite directions. On the casing portion side (right side in FIG. 8) of the impeller 23, a ferromagnetic material (including a permanent magnet and a soft magnetic material) 29 having a ring shape constituting a non-control type magnetic bearing 29 and a soft magnetic material 45 as a sensor target. The nonmagnetic member 46 containing these is provided.

  The actuator unit 40 is provided with the rotor 12 supported by the motor bearing 11 constituted by a rolling bearing, a dynamic pressure bearing, or the like so as to face the side of the impeller 23 having the permanent magnet 24. The rotor 12 is driven to rotate by a radial gap motor formed by the motor stator 16 and the motor rotor 15 facing each other in the radial direction. The rotor 12 is provided with the same number of permanent magnets 14 as the permanent magnets 24 of the impeller 23 so as to face the permanent magnets 24 of the impeller 23 and to exert an attractive force. In this permanent magnet 14 as well, adjacent magnets are magnetized with magnetic poles in opposite directions.

  A synchronous motor including a DC brushless motor, an asynchronous motor including an induction motor, or the like is used for the motor unit 13 including the motor rotor 15 and the motor stator 16.

  An electromagnet 31 is provided so as to face the soft magnetic member 26 of the impeller 23. On the other hand, the magnetic sensor 222 is disposed so as to face the soft magnetic material 45 of the impeller 23, and the ring-shaped permanent magnet 28 is disposed so as to face the ferromagnetic body 29.

  Further, the impeller 23 can move in the axial direction in the pump chamber 22, but the attractive force acting between the permanent magnet 24 and the permanent magnet 14 within the movable range is larger than that between the permanent magnet 28 and the ferromagnetic material 29. The material and shape of each of the permanent magnet 28 and the ferromagnetic material 29 and the position at which the permanent magnet 28 is disposed are set so that the attractive force acting on the magnet is always increased.

  By the magnetic sensor 222 and the electromagnet 31, in the pump chamber 22, the attractive force between the permanent magnet 24 and the permanent magnet 14, the attractive force between the ferromagnetic material 29 and the permanent magnet 28, and the fluid force acting on the impeller 23 during pumping Accordingly, the impeller 23 can be held at the center of the pump chamber 22. In FIG. 8, the magnetic sensor 222 for measuring the position of the impeller 23 is in the casing unit 50, but the magnetic sensor 222 can be placed on the actuator unit 40 (see Patent Document 2).

Japanese Patent Laid-Open No. 2002-21773 JP 2002-130177 A

  In the magnetic levitation pump device of the first conventional example shown in FIG. 7, since the electromagnet 31 and the magnetic sensor 222 are arranged close to the space on the same side with respect to the impeller 23, There is a problem in that the magnetic flux generated by energization affects the magnetic sensor 222 and the exact position of the impeller 23 cannot be detected.

  In the magnetic levitation pump device of the second conventional example shown in FIG. 8, the electromagnet 31 and the magnetic sensor 222 are arranged in the space on the opposite side to the impeller 23, but the entire pump When the magnetic sensor 222 is placed on the actuator unit 40 in order to reduce the size of each component for compactness, the magnetic sensor 222 and the electromagnet 31 are close to each other. Similar to the conventional example, the magnetic flux generated by energizing the electromagnet 31 affects the magnetic sensor 222, and there is a problem that the position of the impeller 23 cannot be detected accurately.

These problems will be described in more detail.
FIG. 10 is a diagram illustrating the relationship between the electromagnet current Im flowing through the electromagnet 31 and the drift amount (sensor shift amount) Sf in the sensor output Sa in the controller 200 of the prior art of FIG.

  Referring to FIG. 10, when no electromagnet current Im is passed through electromagnet 31, this drift does not occur. When an electromagnet current Im greater than a certain current is passed, drift occurs in sensor output Sa.

  The electromagnet current Im increases when the electromagnet current Im is not passed through the electromagnet 31 and when the electromagnet current Im is flown to “lift” the impeller 23 or when an excessive external force is applied to the impeller 23. At this time, magnetic flux noise from the electromagnet 31 greatly affects the magnetic sensor 222, and if the impeller 23 is supported by the magnetic bearing using the sensor output Sa at this time, the impeller 23 may not be stably lifted. There was sex.

  In particular, when the impeller 23 is lifted, an excessive electromagnet current Im flows through the electromagnet 31. The reason why this excessive electromagnet current Im flows is, for example, in the first conventional example of FIG. 7 described above. That is, when the electromagnet 31 is not activated, the impeller 23 is attracted to the partition wall 33 on the rotor 12 side by the attractive force between the impeller-side permanent magnet 24 and the rotor-side permanent magnet 14. When the impeller 23 is magnetically levitated by the electromagnet 31 in this state, since the magnetic levitation of the impeller 23 is integrated and controlled by the PID compensator 224, an excessive current more than necessary flows immediately after the electromagnet 31 is activated. As a result, the magnetic sensor output drifts and the impeller 23 cannot be accurately detected.

  As described above, in the conventional magnetic levitation type pump device illustrated in FIGS. 7 to 9, since the magnetic magnet for the magnetic bearing and the magnetic sensor are close to each other, the magnetic flux generated by energizing the electromagnet for the magnetic bearing Affects the magnetic sensor, and there has been a problem that accurate position detection of the impeller and stable magnetic levitation cannot be performed.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic levitation pump device that suppresses the influence of magnetic flux from an electromagnet for a magnetic bearing to a magnetic sensor as much as possible, enables stable position measurement of the impeller, and thus stable magnetic levitation. It is to be.

According to one aspect of the present invention, a pump unit that discharges fluid by rotating an impeller in a casing, a rotary drive unit that rotates the impeller coupled to the impeller in a non-contact manner by magnetic force, and the floating of the impeller A magnetic sensor for detecting the position, a sensor circuit for outputting a signal indicating the flying position of the impeller based on the detection result of the magnetic sensor, and a current command for floating the impeller in the casing based on the output signal of the sensor circuit A magnetic sensor in which a magnetic sensor and an electromagnet are arranged close to each other, and includes a PID compensator that generates a value, an electromagnet for applying an electromagnetic force to the impeller, and a power amplifier that causes a current to flow through the electromagnet according to a current command value In a floating pump device, a limit circuit that limits the current command value to a value below the upper limit between the PID compensator and the power amplifier It is provided, the upper limit value is obtained by the features that you have been set based on the current required to levitate the impeller which is located the end opposite the electromagnet in the casing.

According to another aspect of the present invention, a pump unit that discharges a fluid by rotating an impeller in a casing, a rotary drive unit that rotates the impeller coupled to the impeller in a non-contact manner by a magnetic force, and the floating of the impeller A magnetic sensor for detecting the position, a sensor circuit for outputting a signal indicating the flying position of the impeller based on the detection result of the magnetic sensor, and a current command for floating the impeller in the casing based on the output signal of the sensor circuit A magnetic sensor in which a magnetic sensor and an electromagnet are arranged close to each other , including a PID compensator for generating a value, an electromagnet for applying an electromagnetic force to the impeller, and a power amplifier for causing a current to flow through the electromagnet according to a current command value in floating pump device, between the sensor circuit and the PID compensator, to limit the level of the output signal of the sensor circuit to limit the following values Limit circuit is provided, the upper limit value is obtained by the features that you have been set based on the maximum value of the output signal level of the sensor circuit when the impeller moves within the movable range in the casing.

According to still another aspect of the present invention, the limit circuit includes a Zener diode that limits the level of the output signal of the sensor circuit to an upper limit value or less .

  According to still another aspect of the present invention, the magnetic levitation pump device is a blood pump device.

  Therefore, according to the present invention, since the influence of the magnetic flux from the electromagnet for the magnetic bearing on the magnetic sensor can be suppressed, the accuracy of the position data of the impeller to be measured can be increased. Therefore, stable magnetic levitation performance can be obtained when the impeller is magnetically levitated.

1 is a schematic block diagram of a magnetic levitation pump device according to a first embodiment of the present invention. FIG. 2 is a circuit diagram illustrating a specific configuration of a low-pass filter and a sensor compensation circuit illustrated in FIG. 1. It is a figure which shows the relationship between the sensor compensation output and the electromagnet current in the magnetic levitation type pump apparatus by 1st Embodiment of this invention. It is a schematic block diagram of the magnetic levitation type pump device by a 2nd embodiment of this invention. It is a figure which shows the relationship between the PID compensator output in the magnetic levitation type pump apparatus by 2nd Embodiment of this invention, and an electromagnet current command value. It is a schematic block diagram of the magnetic levitation type pump device by a 3rd embodiment of this invention. It is a longitudinal cross-sectional view of the magnetic levitation pump device of the first conventional example. It is a longitudinal cross-sectional view of the magnetic levitation type pump apparatus of the 2nd prior art example. It is a schematic block diagram of the magnetic levitation type pump apparatus of the 1st and 2nd prior art example. It is a figure which shows the relationship between the sensor shift amount and electromagnet current in the conventional magnetic levitation type pump apparatus.

  FIG. 1 is a schematic block diagram showing the overall configuration of a magnetic levitation pump device according to a first embodiment of the present invention. The first embodiment shown in FIG. 1 is different from the conventional magnetic levitation pump device shown in FIG. 9 in the following points. That is, in the magnetic levitation pump device shown in FIG. 1, a resistor R1 for measuring the electromagnet current Im is provided, and the electromagnet current measurement value Id measured by the resistor R1 is given to the low-pass filter 220 to thereby generate high-frequency noise. Remove. Next, with respect to the current measurement value Id ′ output from the low-pass filter 220, a correction calculation derived from the relationship (for example, see FIG. 10) between the electromagnet current value Im measured and calculated in advance and the sensor drift amount Sf is subjected to sensor compensation. The circuit 230 outputs the sensor compensation output Sm. The sensor circuit output Sb is compensated by adding / subtracting the sensor compensation output Sm with the sensor circuit output Sb.

  FIG. 2 is a circuit diagram showing a configuration example in which the low-pass filter 220 and the sensor compensation circuit 230 shown in FIG. 1 are realized by analog arithmetic circuits. Referring to FIG. 2, the low-pass filter 220 includes a resistor R2, a capacitor C1, and an operational amplifier A1.

  The sensor compensation circuit 230 includes resistors R4, R5, R6, R7, and R8, operational amplifiers A2 and A3, diodes D1 and D2, and a variable resistor VR1.

  Here, the time constant of the low-pass filter 220 is determined by R2 × C1, and its gain is l times. If R4 = R5 = R6, the output Sm is zero when the output of the low-pass filter 220 is equal to or lower than the voltage Sh set by VR1, and the output voltage of the low-pass filter 220 is equal to or higher than Sh. The output voltage is Sm = (R8 / R7) × (Vd−Sh). Here, Vd = Id × R1.

  FIG. 3 shows the measured electromagnet current Id on the horizontal axis when the influence of the magnetic flux on the magnetic sensor 222 from the adjacent magnetic bearing electromagnet 31 in the first embodiment shown in FIG. The shift sensor amount Sf at that time is plotted on the vertical axis, and the relationship is indicated by a solid line. That is, when the electromagnet current measurement value Id proportional to the electromagnet current Im is small, the sensor shift amount Sf is zero, and when the electromagnet current measurement value Id exceeds a certain value, the sensor shift amount Sf is the electromagnet current value. It increases almost in proportion to the amount of increase in Id. FIG. 3 also shows a sensor compensation output Sm (broken line) obtained by adjusting Sh and (R8 / R7) shown in FIG. 2 in order to compensate for the sensor shift amount Sf.

  Since the sensor compensation circuit 230 shown in FIG. 2 makes the sensor compensation output Sm completely proportional to the increase amount of the electromagnet current measurement value Id, the actual sensor shift amount Sf and the sensor compensation output Sm do not completely match. A pretty good approximation. That is, as shown in FIG. 1, by subtracting the sensor compensation output Sm from the actual sensor output Sb, it is possible to cancel the influence on the sensor output that changes due to the electromagnet current Im.

  Here, in FIG. 2, the correction circuit is configured by an analog circuit, but this may be realized by a digital circuit or software.

  As described above, according to the first embodiment, the accuracy of the position measurement of the impeller can be improved by compensating the sensor circuit output based on the actual measurement value of the electromagnet current for the magnetic bearing. Stable magnetic levitation performance can be realized.

  Next, FIG. 4 is a schematic block diagram showing the configuration of the magnetic levitation pump device according to the second embodiment of the present invention. The second embodiment shown in FIG. 4 is different from the conventional magnetic levitation pump device shown in FIG. 9 in the following points. That is, in the magnetic levitation pump device shown in FIG. 4, the limit circuit 210 is provided between the PID compensator 224 and the power amplifier 225.

  Referring to FIG. 4, sensor output Sa from magnetic sensor 222 is input to sensor circuit 223, converted by internal conversion function f (Sb), and output as sensor circuit output Sb. The sensor circuit output Sb is input to the PID compensator 224, converted by the internal conversion function f (Sp), and output as the PID compensator output Sp. The limit circuit 210 receives the PID compensator output Sp, converts it by an internal conversion function f (Se), and outputs it as an electromagnet current command value Sd. The electromagnet current command value Sd is input to the power amplifier 225, and the power amplifier 225 outputs the electromagnet current Im and supplies it to the electromagnet 31.

  FIG. 5 is a diagram showing the relationship of the electromagnet current command value Sd (vertical axis) to the PID compensator output Sp (horizontal axis). In the second embodiment of FIG. 4, a limit circuit 210 is provided between the PID compensator 224 and the power amplifier 225. As shown in FIG. 5, the limit circuit 210 limits the output value of the electromagnet current command value Sd, which is the input of the power amplifier 225, to the upper limit value B when the PID compensator output Sp is a certain value A or more. The electromagnet current Im of the electromagnet 31 for magnetic bearings also has an upper limit.

  The limit circuit 210 can be configured to limit the PID compensator output Sp using, for example, a Zener diode. Alternatively, the limit circuit 210 may be configured to limit the PID compensator output Sp using an operational amplifier or the like instead of the Zener diode.

  In the case of the pump configuration shown in FIG. 7, the maximum value of the current flowing through the electromagnet 31 is the current value necessary to move the impeller 23 in the right direction in the figure when the impeller 23 is on the motor side (left in the figure). It becomes. Therefore, it is possible to prevent the electromagnet current Im from flowing more than necessary by providing a limit for the current value that is about 1.5 times the estimated current maximum value. As described above, as a result of not passing an unnecessarily large electromagnet current Im to the magnetic bearing electromagnet 31, it is possible to limit the maximum value of the sensor drift amount Sf.

  In the block diagram shown in FIG. 4, the limit circuit 210 is provided between the PID compensator 224 and the power amplifier 225. However, a limit circuit is inserted between the power amplifier 225 and the magnetic bearing electromagnet 31. However, the same effect can be obtained.

  As described above, according to the above-described second embodiment, by providing a limit to the electromagnet current in advance, the accuracy of the impeller position measurement can be increased, and the stable magnetic levitation performance of the impeller can be realized.

  Next, FIG. 6 is a schematic block diagram showing a configuration of a magnetic levitation pump device according to a third embodiment of the present invention. The third embodiment shown in FIG. 6 is different from the second embodiment shown in FIG. 4 in the following points. That is, in the magnetic levitation pump device of the third embodiment shown in FIG. 6, a limit circuit 210Z including a Zener diode ZD1 is provided between the sensor circuit 223 and the PID compensator 224. More specifically, in FIG. 6, a Zener diode ZD1 is connected between the output of the sensor circuit 223 and the ground potential, and the maximum voltage value of the sensor circuit output Sb of the sensor circuit 223 is limited by the Zener diode ZD1. Then, it is given to the PID compensator 224 to limit the value of the electromagnet current command value Sd.

  In the magnetic levitation type pump device, the impeller 23 is located in a limited place in the pump chamber 22, and therefore the output of the magnetic sensor 222 is also in a limited range. Here, when the magnetic sensor 222 is affected by the electromagnet 31 and the sensor output Sa drifts, the sensor output Sa has a value as if the impeller 23 is outside the movable range in the pump chamber. May show.

  Therefore, in the magnetic levitation pump device according to the third embodiment of the present invention shown in FIG. 6, an upper limit of the drift amount in the sensor output is set by providing a limit to the sensor output itself.

  Referring to FIG. 6, a limit circuit 210 </ b> Z composed of a Zener diode ZD <b> 1 is connected between the sensor circuit 223 and the PID compensator 224. The sensor circuit output Sb is limited to the Zener voltage of the Zener diode ZD 1 and is input to the PID compensator 224. The PID compensator 224 outputs an electromagnet current command value Sd in accordance with the sensor circuit output Sb limited by the Zener voltage, and the electromagnet current command value Sd is amplified by the power amplifier 225 to form an electromagnet current Im as a magnetic bearing. Is output to the electromagnet 31. Since the sensor circuit output Sb is limited to the Zener voltage of the Zener diode ZD1, an excessive electromagnet current Im can be prevented.

  As described above, in the magnetic levitation pump device according to the third embodiment of the present invention, even when there is a drift in the magnetic sensor output due to the influence of the electromagnet, the sensor output exceeds the movable range of the impeller in the pump chamber. In this case, it is possible to prevent the value from being in a certain position and to improve the accuracy of the position measurement of the impeller, and to realize stable magnetic levitation of the impeller.

  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.

  DESCRIPTION OF SYMBOLS 1 Magnetic levitation type pump apparatus main body, 10 Motor part, 11 Motor bearing, 12 Rotor, 13 Motor, 14, 24, 28 Permanent magnet, 15 Motor rotor, 16 Motor stator, 20 Pump part, 21 Casing, 22 Pump chamber, 23 Impeller , 25, 46 Non-magnetic member, 26, 45 Soft magnetic member, 29 Ferromagnetic material, 30 Magnetic bearing portion, 31 Electromagnet, 33, 34, 35, 36 Bulkhead, 40 Actuator portion, 50 Casing portion, 200 Controller, 210 , 210Z limit circuit, 220 low-pass filter, 222 magnetic sensor, 223 sensor circuit, 225 power amplifier, 224 PID compensator, 230 sensor compensation circuit, 232 addition / subtraction circuit.

Claims (4)

A pump unit that discharges fluid by rotating the impeller in the casing, a rotational drive unit that rotates the impeller coupled to the impeller in a non-contact manner by magnetic force, and a magnetic type that detects the floating position of the impeller A sensor circuit that outputs a signal indicating a floating position of the impeller based on a detection result of the magnetic sensor, and a current command value for floating the impeller in the casing based on an output signal of the sensor circuit A PID compensator for generating an electromagnetic force, an electromagnet for applying an electromagnetic force to the impeller, and a power amplifier for causing a current to flow through the electromagnet according to the current command value , wherein the magnetic sensor and the electromagnet are close to each other In the magnetic levitation pump device to be arranged,
A limit circuit is provided between the PID compensator and the power amplifier to limit the current command value to a value equal to or less than an upper limit value .
The upper limit was characterized that you have been set based on the current required to levitate the impeller which is located at the opposite end with said electromagnet in said casing, maglev pump apparatus. A pump unit that discharges fluid by rotating the impeller in the casing, a rotational drive unit that rotates the impeller coupled to the impeller in a non-contact manner by magnetic force, and a magnetic type that detects the floating position of the impeller A sensor circuit that outputs a signal indicating a floating position of the impeller based on a detection result of the magnetic sensor, and a current command value for floating the impeller in the casing based on an output signal of the sensor circuit A PID compensator for generating an electromagnetic force, an electromagnet for applying an electromagnetic force to the impeller, and a power amplifier for causing a current to flow through the electromagnet according to the current command value , wherein the magnetic sensor and the electromagnet are close to each other In the magnetic levitation pump device to be arranged,
A limit circuit is provided between the sensor circuit and the PID compensator to limit the level of the output signal of the sensor circuit to a value equal to or lower than an upper limit value .
The upper limit was characterized that you have been set based on the maximum value of the output signal level of the sensor circuit in the case where the impeller within the movable range in the casing is moved, maglev pump apparatus. The limit circuit, the level of the output signal of the sensor circuit is characterized in that it comprises a Zener diode to limit below the upper limit, maglev pump apparatus according to 請 Motomeko 2.   4. The magnetic levitation pump device according to claim 1, wherein the magnetic levitation pump device is a blood pump device.

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