Motor fault detection method and device

Abstract

The embodiment of the invention discloses a motor fault detection method and device, and the method comprises the steps: enabling a control unit to apply an excitation signal to a first winding unit before a motor is started; first current, second current and third current are obtained, the first current is current flowing through the first winding unit, the second current is current flowing through the second winding unit, and the third current is current flowing through the third winding unit; and according to the first current, the second current and the third current, detecting whether the motor has an open phase and an open-phase winding unit. Before the motor is started, whether the open phase exists in the stator or not can be detected only by applying the excitation signal to the one-phase winding unit, the heating value of the motor can be reduced as much as possible while the open phase is simply and conveniently detected, and therefore the motor and the impeller are protected.

Description

Technical Field

[0001] The present application relates to the field of medical device technology, and in particular to a motor fault detection method and device. Background Art

[0002] An intravascular ventricular assist device is an artificial mechanical device that can be inserted into the patient's heart through the patient's blood vessels. The intravascular ventricular assist device is set on the heart valve so that the ventricular assist device can pump blood in the ventricle into the artery. The miniature ventricular assist device needs to pass through the patient's blood vessels to reach the left ventricle. Its size is very small, so the motor size in the ventricular assist device must be very small. This small size of the motor can easily cause coil damage during the assembly and implantation of the ventricular assist device, causing the motor to work abnormally or become unusable. Summary of the invention

[0003] The embodiments of the present application provide a motor fault detection method and device, which can simply and quickly detect whether a winding unit is missing a phase.

[0004] In a first aspect, an embodiment of the present application provides a motor fault detection method, which is applied to a ventricular assist device, wherein the ventricular assist device includes an impeller, a motor for driving the impeller to rotate, and a control unit for controlling the motor, wherein the motor includes a three-phase winding, wherein the three-phase winding includes a first winding unit, a second winding unit, and a third winding unit; the method includes:

[0005] Before starting the motor, applying an excitation signal to the first winding unit;

[0006] Obtaining a first current, a second current, and a third current, wherein the first current is a current flowing through the first winding unit, the second current is a current flowing through the second winding unit, and the third current is a current flowing through the third winding unit;

[0007] Whether there is a phase loss and a phase loss winding unit of the motor is detected according to the first current, the second current, and the third current.

[0008] In a second aspect, an embodiment of the present application provides a control unit of a ventricular assist device, the ventricular assist device comprising an impeller, a motor for driving the impeller to rotate, and a control unit for controlling the motor, the motor comprising a three-phase winding, the three-phase winding comprising a first winding unit, a second winding unit, and a third winding unit; the control unit comprises one or more processing units, the one or more processing units being used to:

[0009] Before starting the motor, applying an excitation signal to the first winding unit;

[0010] Obtaining a first current, a second current, and a third current, wherein the first current is a current flowing through the first winding unit, the second current is a current flowing through the second winding unit, and the third current is a current flowing through the third winding unit;

[0011] Whether there is a phase loss and a phase loss winding unit of the motor is detected according to the first current, the second current, and the third current.

[0012] In a third aspect, an embodiment of the present application provides a ventricular assist device, the ventricular assist device comprising:

[0013] impeller;

[0014] A motor driving the impeller to rotate, the motor comprising a three-phase winding, the three-phase winding comprising a first winding unit, a second winding unit and a third winding unit;

[0015] A control unit for controlling the motor, wherein the control unit is used to execute part or all of the steps described in the method described in the first aspect above.

[0016] In a fourth aspect, an embodiment of the present application provides a medical device, comprising a processor, a memory, a communication interface, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, and the program includes instructions for executing some or all of the steps described in the method described in the first aspect above.

[0017] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute some or all of the steps described in the method described in the first aspect above.

[0018] In a sixth aspect, an embodiment of the present application provides a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute some or all of the steps described in the method described in the first aspect of the embodiment of the present application. The computer program product may be a software installation package.

[0019] The technical solution provided by the present application is that before starting the motor, the control unit applies an excitation signal to the first winding unit; then obtains the first current, the second current and the third current, the first current is the current flowing through the first winding unit, the second current is the current flowing through the second winding unit, and the third current is the current flowing through the third winding unit; detects whether the motor has a phase loss and a phase loss winding unit based on the first current, the second current and the third current. The present application can detect whether there is a phase loss in the stator by applying an excitation signal to a single-phase winding unit before the motor is started, and can detect the phase loss simply and conveniently while reducing the heat generated by the motor as much as possible, thereby protecting the motor and the impeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a structural schematic diagram of a motor provided in an embodiment of the present application;

[0022] Figure 2 is a schematic diagram of the structure of another motor provided in an embodiment of the present application;

[0023] Figure 3 It is a flow chart of a motor fault detection method provided in an embodiment of the present application;

[0024] Figure 4 It is a schematic diagram of the principle of a control unit driving a three-phase winding provided in an embodiment of the present application;

[0025] Figure 5 It is a structural schematic diagram of a medical device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to help those skilled in the art better understand the technical solutions of the present application, the following is a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the description of the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0027] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, software, product, or device that includes a series of steps or units is not limited to the listed steps or units, but also includes steps or units that are not listed, or also includes other steps or units inherent to these processes, methods, products, or devices.

[0028] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0029] The motor involved in the present application may be a motor in a medical assist device, which may be a mechanical circulatory support system for protection of Percutaneous Coronary Intervention (PCI) surgery. The medical assist device may be a blood pump, which may include a ventricular assist device (VAD), which may be installed in the left ventricle or right ventricle of the heart. The distal end of the ventricular assist device passes through the heart valve (such as the aortic valve, the mitral valve) and is located in the ventricle inside the heart, and the proximal end of the ventricular assist device is located in the blood vessels outside the heart (such as the aorta, the pulmonary artery), so as to pump the blood in the ventricle into the blood vessels through the ventricular assist device, thereby assisting the pumping function of the heart.

[0030] For example, the ventricular assist device includes a motor, an impeller and a control unit. The motor is connected to the impeller in a transmission manner to drive the impeller to rotate. The control unit controls the current flowing through the motor to control the torque generated by the motor, thereby controlling the rotation speed of the impeller. The motor includes a stator, a rotor, a rotating shaft and a housing. The rotor is fixedly connected to the rotating shaft, and the rotor and the rotating shaft are rotatably mounted on the housing. The rotating shaft is connected to the impeller so that the impeller is driven to rotate when the rotor rotates. The rotating shaft is rotatably mounted on the housing, and the rotating shaft extends roughly along the axial direction of the housing or the axis extension direction of the rotating shaft is roughly consistent with the axial direction of the housing. The stator is fixedly mounted on the housing, that is, the stator is arranged in the inner cavity of the housing, and the rotating shaft is rotatably penetrated by the stator. The rotor is located in the housing and is fixedly connected to the rotating shaft. The rotor has magnetism, and the stator can generate a rotating magnetic field that drives the rotor to rotate, so that the stator can drive the rotor to rotate, and the rotor drives the rotating shaft to rotate.

[0031] See also Figure 1 , Figure 1 is a schematic diagram of the structure of a motor provided in an embodiment of the present application. Figure 1 As shown, the motor 10 includes a housing 100, a rotating shaft 200, a first rotor 310, and a first stator 410. A portion of the rotating shaft 200 is accommodated in the housing 100, and a portion thereof extends outside the housing 100 and is fixedly connected to the impeller of the ventricular assist device, and the rotating shaft 200 can rotate relative to the housing 100; the first rotor 310 and the first stator 410 are both accommodated in the housing 100; the first rotor 310 is fixedly connected to the rotating shaft 200, and the first rotor 310 can rotate relative to the housing 100, so that the first rotor 310 can drive the rotating shaft 200 to rotate; the first stator 410 can drive the first rotor 310 to rotate.

[0032] Specifically, the first rotor 310 has magnetism, and the first stator 410 can generate a rotating magnetic field that drives the first rotor 310 to rotate. The first rotor 310 includes a plurality of magnets, and the plurality of magnets are fixedly connected to the rotating shaft 200. For example, the plurality of magnets can be arranged along the same circle in a certain manner, such as a Halbach array.

[0033] In the illustrated embodiment, the motor 10 further includes a second rotor 320, which is fixedly connected to the rotating shaft 200, and the first stator 410 can also drive the second rotor 310 to rotate. The second rotor 320 is also accommodated in the housing 100; the first stator 410 is located between the first rotor 310 and the second rotor 320. The second rotor 320 also includes a plurality of magnets, which are fixedly connected to the rotating shaft 200. For example, the plurality of magnets of the second rotor 320 can be arranged along the same circle in a certain manner, such as a Halbach array.

[0034] The first stator 410 includes 3N winding units, which are arranged symmetrically on a circle, and the first rotor 310 and the second rotor 320 are driven to operate by inputting three-phase alternating current into each three-phase winding, and N can be 1, 2, 3, 4, etc. For example, each winding unit includes a stator tooth and a stator coil, and the rotation speed of the first rotor 310 can be controlled by controlling the current flowing through the stator coil.

[0035] See also Figure 2 , Figure 21 is a schematic diagram of the structure of another motor provided by an embodiment of the present application. The motor 10 includes a housing 100, a rotating shaft 200, a first stator 410, a first rotor 310, a second stator 420, and a second rotor 320. A portion of the rotating shaft 200 is accommodated in the housing 100, and a portion extends outside the housing 100 and is used to be fixedly connected to the impeller of the ventricular assist device. The rotating shaft 200 can rotate relative to the housing 100; the first rotor 310, the second rotor 320, the first stator 410, and the second stator 420 are all accommodated in the housing 100; the first rotor 310 and the second rotor 320 are fixedly connected to the rotating shaft 200, and the first rotor 310 and the second rotor 320 can rotate relative to the housing 100, so that the first rotor 310 and the second rotor 320 can drive the rotating shaft 200 to rotate; the first stator 410 can drive the first rotor 310 to rotate, and the second stator 420 can drive the second rotor 320 to rotate.

[0036] Specifically, the first rotor 310 and the second rotor 320 are both magnetic, the first stator 410 can generate a rotating magnetic field that drives the first rotor 310 to rotate, and the second stator 420 can generate a rotating magnetic field that drives the second rotor 320 to rotate. The first rotor 310 and the second rotor 320 each include a plurality of magnets, which are fixedly connected to the rotating shaft 200. For example, the plurality of magnets can be arranged along the same circle in a certain manner, such as a Halbach array.

[0037] The first stator 410 and the second stator 420 each include 3N winding units, which are arranged symmetrically on a circle. The first rotor 310 and the second rotor 320 are driven to operate by inputting three-phase alternating current into each three-phase winding. For example, each winding unit includes a stator tooth and a stator coil. The control unit can control the rotation speed of the first rotor 310 by controlling the current flowing through the stator coil in the first stator 410, and control the rotation speed of the second rotor 320 by controlling the current flowing through the stator coil in the second stator 420.

[0038] In the present application, N may be 1, 2, 3, 4, etc. After satisfying the above structure, no matter the number of winding units is 3, 6, 9 or more, the control unit can monitor the rotation speed of the first rotor 310 and the second rotor 320 in real time to realize the operation of the motor 10.

[0039] The ventricular assist device needs to pass through the blood vessels to enter the heart, so the size of the ventricular assist device is very small, and the size of the motor 10 set in the ventricular assist device is even smaller, so that the stator coil in each phase winding unit of the motor 10 is very small. The small stator coil is at risk of disconnection or damage during the operation of the ventricular assist device (for example, severe heating of the stator coil), which makes the winding unit prone to short circuit. If the motor 10 is started in the absence of a phase, it will cause the motor 10 to run unsteadily, and it will also cause the current of the normal winding outside the short-circuited winding unit to increase, which will further aggravate the damage of the motor 10, and in severe cases, it will cause the motor 10 to stop unexpectedly, affecting user safety. Therefore, before starting the motor 10, it is necessary to detect whether the motor 10 is missing a phase to ensure that the motor 10 will not operate in the absence of a phase.

[0040] Based on this, the present application proposes a motor fault detection method. Before the motor 10 is started, an excitation signal is applied to any winding unit in the three-phase winding, and the collected current flowing through each phase winding unit is compared with the preset current to detect whether there is a phase missing in the three-phase winding and the winding unit with the phase missing.

[0041] In combination with the above description, the present application is described below from the perspective of method examples.

[0042] See also Figure 3 , Figure 3 A flow chart of a motor fault detection method provided in an embodiment of the present application, combined with Figure 1 and Figure 2 The motor 10 shown in the figure is used as an example for description. Figure 3 As shown, the method includes the following steps.

[0043] S310: Before starting the motor, apply an excitation signal to the first winding unit.

[0044] The first stator 410 is generally annular and includes 3N winding units arranged symmetrically on a circle. Three winding units can form a three-phase winding, and the control unit can control the rotation speed of the first rotor 310 by controlling the current flowing through each phase winding unit in the three-phase winding.

[0045] The first stator 410 includes three-phase windings, and the winding units in the three-phase winding unit can be recorded as a first winding unit, a second winding unit, and a third winding unit. It can be understood that the first winding unit, the second winding unit, and the third winding unit are only used to distinguish the three-phase windings, and do not specifically refer to a specific winding unit in the three-phase windings.

[0046] For example, the motor 10 may be a three-phase brushless DC motor, and the stator 410 has three winding units controlled by different corresponding phases U, V, W of the voltage input of the three-phase motor control. The ventricular assist device 100 may receive a three-phase input of alternating current, and each three-phase current is equally separated by a phase difference of 120 degrees. Figure 4 As shown, one end of the three winding units Lu, Lv, Lw in the three-phase winding is connected to the corresponding intermediate nodes MN1, MN2, MN3 of the three half-bridges H1, H2, H3 through the corresponding power lines L1, L2, L3 respectively. The three half-bridges H1, H2, H3 respectively include two semiconductor switches, such as field effect transistors (MOSFET tubes), which are shown as switches Su1 and Su2, Sv1 and Sv2, Sw1 and Sw2; the other ends of the three winding units Lu, Lv, Lw are connected to each other, so that a loop is formed between every two phase winding units to generate a magnetic field.

[0047] Among them, each of the three half-bridges H1, H2, and H3 defines a respective phase power line drive unit controlled by a control unit. The three half-bridges H1, H2, and H3, i.e., the phase power line drive units, can be integrated or implemented by one drive unit DU. Each of the half-bridges H1, H2, and H3 is controlled by a control unit, and the control unit is configured to control respective switches Su1 and Su2, Sv1 and Sv2, Sw1 and Sw2 by pulse width modulation, so that the waveform of the voltage driving a specific winding unit Lu, Lv, and Lw has a phase difference of 120° relative to any one of the waveforms of the respective voltages driving the other two motor windings. The half-bridges H1, H2, and H3 are respectively connected to the control unit, and the control unit switches the respective currents provided to the corresponding winding units Lu, Lv, and Lw by switching the respective half-bridges H1, H2, and H3, resulting in corresponding changes in the magnetic field generated by the specific winding unit. Therefore, the winding unit generates a magnetic field for rotating the rotor of the motor 10.

[0048] Before the ventricular assist device is started, the control unit needs to first detect whether there is a phase loss in the winding unit of the motor 10. After the ventricular assist device is inserted into the left ventricle or the right ventricle and connected to the power supply device, the control unit can perform phase loss detection by applying an excitation signal to the three-phase winding in the stator. Among them, the excitation signal for phase loss detection should be as small as possible to avoid excessive rotation angle of the impeller, and the time for applying the excitation signal should also be as short as possible to avoid increasing the operation time and the heat of the motor, and avoiding the formation of thrombus.

[0049] Specifically, when the ventricular assist device reaches the expected position of the patient, such as the inlet of the ventricular assist device is located in the left ventricle of the patient and the outlet is located in the aorta, before starting the motor 10, the control unit may apply an excitation signal to the first winding unit, and the excitation signal is a pulse signal. For example, the excitation signal is a pulse with a duty cycle of 8% and a duration of 2ms. The pulse signal can reduce the heat generated by the motor and protect the motor to the maximum extent (the impeller only swings once when the pulse signal is applied to the first winding unit).

[0050] It should be noted that the excitation signal can be applied to any phase winding unit in the three-phase winding, that is, the control unit can apply the excitation signal to the first winding unit, and can also apply the excitation signal to the second winding unit, and can also apply the excitation signal to the third winding unit. This application does not limit this.

[0051] S320, obtaining a first current, a second current and a third current, wherein the first current is a current flowing through the first winding unit, the second current is a current flowing through the second winding unit, and the third current is a sampled current of the third winding unit.

[0052] After applying the excitation signal, the control unit can detect the current value flowing through each phase winding unit. A phase current detection current can be set on each phase winding unit to detect the current flowing through the phase winding unit. The phase current detection current can be connected to the control unit and the detected current can be fed back in real time. When the winding unit in the three-phase winding is not normally in an open circuit state, the phase winding unit forms a loop with the winding units of other phases through the phase power supply line. When the control unit applies an excitation signal to the first winding unit, the phase current detection current detects that the current value flowing through the loop is the same or similar to the applied excitation signal. Therefore, when the current value of the phase winding unit is not detected by the control unit or the current value of the phase winding unit is abnormally small, it means that the circuit of the phase winding unit may have a circuit breaker fault, and the phase winding unit is missing a phase.

[0053] S330, detecting whether the motor has a missing phase and a missing phase winding unit according to the first current, the second current, and the third current.

[0054] When a phase is missing in the three-phase winding, the winding unit of the missing phase cannot form a loop with other winding units, so the phase current detection circuit may not be able to detect the current flowing through the winding unit of the phase.

[0055] In the present application, whether there is a phase loss and a phase loss winding unit in the three-phase winding can be detected simply by applying an excitation signal to any phase winding unit in the three-phase winding, thereby achieving fast and simple phase loss detection.

[0056] Optionally, detecting whether the motor has a phase loss and a phase-missing winding unit based on the first current, the second current and the third current includes: comparing the first current, the second current and the third current with a preset current respectively; if the first current, the second current and the third current are all greater than the preset current, determining that the motor does not have a phase loss; if any one of the first current, the second current and the third current is less than or equal to the preset current, determining that the motor has a phase loss, and determining the phase-missing winding unit based on the number of the first current, the second current and the third current that are less than or equal to the preset current.

[0057] Among them, the determining of the phase-missing winding unit according to the number of the first current, the second current and the third current that are less than or equal to the preset current includes: if the first current, the second current and the third current are all less than or equal to the preset current, determining that the first winding unit is the phase-missing winding unit, or the second winding unit and the third winding unit are the phase-missing winding unit; if the second current is less than or equal to the preset current, and the first current and the third current are greater than the preset current, determining that the second winding unit is the phase-missing winding unit; if the third current is less than or equal to the preset current, and the first current and the second current are greater than the preset current, determining that the third winding unit is the phase-missing winding unit.

[0058] The preset current can be set to 0. For example, when a winding unit is missing a phase, it cannot form a loop with other winding units, so the phase current detection current cannot detect the current value. The preset current can also be set to 1 / 3 of the peak value of the excitation signal. For example, when the terminal of the winding unit is damaged or the contact is poor, although the phase winding unit forms a loop with other winding units, the current value detected by the phase current detection current may be very small.

[0059] Specifically, the first winding unit is denoted as Figure 3The first winding unit is the winding unit Lu, the second winding unit is the winding unit Lv, and the third winding unit is the winding unit Lw. The control unit applies an excitation signal to the winding unit Lu, so that the switch Su1 is in a closed state, so that the power supply Vdc forms a loop through the switch Su1, the power line L1, the winding unit Lu, the winding unit Lv, and the power line L2, and the power supply Vdc forms a loop through the switch Su1, the power line L1, the winding unit Lu, the winding unit Lw, and the power line L3, so the phase current detection current set on each power line can detect the current flowing through each phase winding unit. When the winding unit Lu is not in an open circuit state or poor contact, the values ​​of the first current, the second current and the third current detected by it will all be less than or equal to the preset current; when the winding unit Lv is not in an open circuit state or poor contact, the value of the second current detected by it will be less than or equal to the preset current, while the values ​​of the first current and the third current will be greater than the preset current; when the winding unit Lw is not in an open circuit state or poor contact, the value of the third current detected by it will be less than or equal to the preset current, while the values ​​of the first current and the second current will be greater than the preset current. Therefore, the control unit can directly determine the winding unit with a missing phase based on the current of each phase winding unit.

[0060] In the present application, the motor 10 may be a single-disc motor, that is, a motor having only one stator and one rotor (e.g. Figure 1 The motor 10 may also be a double-disc or multi-disc motor, that is, a motor having two or more rotors and stators (such as Figure 2 When the motor includes a first stator 410 and a second stator 420, before the motor 10 is started, the control unit needs to detect whether there is a phase loss in the first stator 410 and the second stator 420 to ensure the smooth operation of the motor 10. The method for detecting whether the second stator 420 is missing a phase is the same as the method for detecting whether the first stator 410 is missing a phase, and will not be repeated here.

[0061] Furthermore, after the ventricular assist device is started, the winding unit may still cause welding terminal failure, coil breakage, and coil turn short circuit due to long-term operation or excessive load, resulting in phase loss in the three-phase motor. Therefore, the control unit also needs to detect in real time whether there is a phase loss problem in the winding unit in the stator.

[0062] Optionally, the method further includes: during the operation of the motor, detecting whether the first stator has a phase loss; if it is detected that the first stator has a phase loss, obtaining a target speed, wherein the target speed is a preset speed of the ventricular assist device.

[0063] In the embodiment of the present application, in the dual-stator motor 10, the motor 10 may include a first stator 410 and a second stator 420, and the first stator 410 and the second stator 420 respectively drive the first rotor 310 and the second rotor 320 to rotate synchronously. In order to improve the reliability and safety of the operation of the motor 10, during the operation of the motor 10, the control unit can detect in real time whether there is a phase loss in the first stator 410 and the second stator.

[0064] In one possible example, the method also includes: if the target speed is less than or equal to m times the maximum speed, stopping supplying current to the first stator, the maximum speed is the maximum speed allowed by the ventricular assist device, and m is greater than 0 and less than 1; determining a target torque based on the target speed; increasing a target current based on the target torque, the target current being the current flowing through the second stator.

[0065] During the operation of the ventricular assist device, when the control unit detects that the first stator is out of phase, the control unit can obtain the preset speed of the ventricular assist device. The preset speed is the speed set according to the patient's physiological state before the ventricular assist device is started. After the ventricular assist device is started, the pumping flow generated by the constant operation of the ventricular assist device at the preset speed can meet the flow demand of the patient. When the preset speed of the ventricular assist device is relatively small, sufficient torque can be provided by only one stator to enable the ventricular assist device to operate at the desired speed. Therefore, if the target speed is less than or equal to m times the maximum speed, the control unit can directly stop supplying power to the first stator 410 to stop the operation of the first rotor 310. At the same time, in order to maintain the speed required by the ventricular assist device, the control unit can increase the current flowing through the second stator 420 to increase the rotational torque of the second rotor 320.

[0066] Specifically, when there is a phase loss in the first stator 410 and the target speed is less than or equal to m times the maximum speed, the control unit stops the first stator 410 and only relies on the target torque for impeller rotation provided by the second stator 420 to enable the impeller to maintain the previous target speed. When only the second stator 420 is running, the control unit can calculate the target torque to be generated by the second stator 420 when the target speed is reached according to the FOC vector control strategy. The torque is proportional to the current, and the control unit can determine the current flowing through the second stator 420 according to the required target torque. For example, when the first stator 410 stops working due to a phase loss, the target current of the second stator 420 increases by 2 times to enable the motor 10 to have enough torque to maintain the original target speed.

[0067] Similarly, if the control unit detects a phase loss in the second stator 420 during operation of the ventricular assist device, it stops supplying power to the second stator 420 to stop the operation of the second rotor 320 and increases the current flowing through the first stator 410.

[0068] Among them, the detecting whether there is a phase loss in the first stator includes: obtaining multiple sampling currents, the sampling current is the current flowing through the winding unit in the first stator; if it is detected that the target sampling current is less than or equal to the target threshold, it is determined that there is a phase loss in the first stator, and the target sampling current is any one of the multiple sampling currents; otherwise, it is determined that there is no phase loss in the first stator.

[0069] When the winding unit in the three-phase winding is not normally in an open circuit state, the phase winding unit forms a loop with the winding units of other phases through the phase power line. When the motor is running, the phase current detection current can detect the current value flowing through the loop, and the control unit can compare the sampled current flowing through each phase winding unit in the detected three-phase winding with the target threshold to determine whether there is a phase loss in any winding unit. When the winding unit is missing a phase or its terminals are in poor contact, the loop of the phase winding unit cannot be formed, so the detected sampled current will change, such as the sampled current is 0, or the sampled current is much smaller than the current input to the phase winding unit by the control unit. Therefore, when it is detected that the sampled current of the winding unit is less than or equal to the target threshold, it is considered that the phase winding unit circuit may be faulty and there is a phase loss in the first stator 410.

[0070] The target threshold value may be set to 0 or 0.5 mA. Once the control unit detects that the current flowing through the winding unit in the first stator 410 is less than or equal to the target threshold value, it determines that the first stator 410 has a phase loss.

[0071] It should be noted that during the operation of the ventricular assist device, the method for detecting whether the second stator 420 is missing a phase is the same as the method for detecting whether the first stator 410 is missing a phase, and will not be repeated here.

[0072] Furthermore, the method also includes: if the target speed is greater than m times the maximum speed, obtaining an electrical angle set, the electrical angle set being a set of electrical angles of the rotational torque generated by each winding unit in the second stator; and controlling the current flowing through each phase winding unit in the first stator and the second stator according to the electrical angle set, so that the first rotor and the second rotor rotate synchronously.

[0073] In the embodiment of the present application, if there is a phase loss in the first stator 410 or the second stator 420, if the target speed is high, then relying on only one stator cannot provide enough target torque to allow the motor to maintain the previous target speed. Therefore, the first stator 410 with a phase loss continues to operate to provide the motor 10 with torque to maintain the current speed. When any one phase winding unit is missing in the three-phase winding, it can still continue to operate.

[0074] Among them, during the operation of the ventricular assist device, after detecting that there is a phase loss in the first stator 410 or the second stator 420, although the first stator 410 can still drive the first rotor 310 to rotate and the second stator 420 can still drive the second rotor 320 to rotate, the winding unit with the missing phase cannot generate torque, so that the missing phase cannot provide sufficient torque for the motor 10, and the total output torque of the motor 10 is reduced, resulting in a decrease in the actual speed of the motor 10; and the first rotor 310 and the second rotor 320 will rotate out of sync, which will increase the friction of the motor 101, thereby increasing the power consumption of the motor 10, causing the motor 10 to vibrate and the speed to be unstable, thereby reducing the efficiency of the motor 10 and even affecting the operation of the ventricular assist device.

[0075] In addition, since the stator lacks a phase winding unit, the electromagnetic field of the motor 10 is seriously unbalanced at this time. If the electrical angle of the missing phase winding unit is still estimated by the sliding mode observer based on back electromotive force estimation, there will be a large error. Therefore, in the embodiment of the present application, when there is a phase loss in the first stator 410 and the target speed is greater than m times the maximum speed, the control unit can directly use the electrical angle of the second stator 420 to control the first stator 410, so that the first rotor 310 and the second rotor 320 can achieve synchronous operation while ensuring that the speed of the impeller remains unchanged. The first stator 410 causes the speed of the motor 10 to decrease due to the lack of phase. The PI controller inside the control unit can perform feedback adjustment according to the target speed and actual speed of the first stator 410, and increase the target current of the first stator 410 to increase the output torque of the first stator 410.

[0076] Among them, m can be 0.4, 0.5, 0.6, etc. The speed range of the ventricular assist device can be 23000RPM to 46000RPM. For example, when m is 0.5, if the target speed of the ventricular assist device is less than or equal to 23000RPM, when the first stator 410 is detected to be out of phase, the control unit can directly stop providing current to the first stator 410 to stop the operation of the first rotor 310, and provide 2 times the current to the second stator 420; if the target speed of the ventricular assist device is greater than 23000RPM, the control unit can continue to control the current flowing to the first stator 410 at the electrical angle of the second stator 420, so that the electrical angle generated by the first stator 410 is the same as the electrical angle generated by the second stator 420, thereby achieving synchronization between the first rotor 310 and the second rotor 320.

[0077] It can be seen that the present application proposes a motor fault detection method, before starting the motor, the control unit applies an excitation signal to the first winding unit; then obtains the first current, the second current and the third current, the first current is the current flowing through the first winding unit, the second current is the current flowing through the second winding unit, and the third current is the current flowing through the third winding unit; detects whether the motor has a phase loss and a phase loss winding unit based on the first current, the second current and the third current. The present application can detect whether there is a phase loss in the stator by applying an excitation signal to one-phase winding unit before the motor is started, and can reduce the heat generated by the motor as much as possible while simply and conveniently detecting the phase loss, thereby protecting the motor and the impeller.

[0078] The above mainly introduces the scheme of the embodiment of the present application from the perspective of the execution process on the method side. It is understandable that in order to realize the above functions, the network device includes a hardware structure and / or software module corresponding to each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiment provided in this article, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0079] By way of example, the present application also provides a control unit of a ventricular assist device, the ventricular assist device comprising an impeller, a motor for driving the impeller to rotate, and a control unit for controlling the motor, the motor comprising a three-phase winding, the three-phase winding comprising a first winding unit, a second winding unit, and a third winding unit; the control unit comprising one or more processors, the one or more processors being used to: apply an excitation signal to the first winding unit before starting the motor; obtain a first current, a second current, and a third current, the first current being a current flowing through the first winding unit, the second current being a current flowing through the second winding unit, and the third current being a sampled current of the third winding unit; and detect whether the motor has a phase loss and a phase loss winding unit based on the first current, the second current, and the third current.

[0080] For example, the present application also provides a ventricular assist device, the ventricular assist device comprising:

[0081] impeller;

[0082] A motor driving the impeller to rotate, the motor comprising a three-phase winding, the three-phase winding comprising a first winding unit, a second winding unit and a third winding unit;

[0083] A control unit for controlling the operation of the motor, the control unit being used for:

[0084] Before starting the motor, applying an excitation signal to the first winding unit;

[0085] Acquire a first current, a second current, and a third current, wherein the first current is a current flowing through the first winding unit, the second current is a current flowing through the second winding unit, and the third current is a sampled current of the third winding unit;

[0086] Whether there is a phase loss and a phase loss winding unit of the motor is detected according to the first current, the second current, and the third current.

[0087] Among them, the control unit of each of the above schemes has the function of implementing the corresponding steps performed by the medical device in the above method; the functions can be implemented by hardware, or by hardware executing corresponding software.

[0088] In the embodiment of the present application, the control unit may also be a chip or a chip system, such as a system on chip (SoC).

[0089] See also Figure 5 , Figure 5 It is a structural diagram of a medical device provided in an embodiment of the present application, wherein the medical device comprises: one or more processors, one or more memories, one or more communication interfaces, and one or more programs; the one or more programs are stored in the memories and are configured to be executed by the one or more processors.

[0090] The above program includes instructions for performing the following steps:

[0091] Before starting the motor, applying an excitation signal to the first winding unit;

[0092] Acquire a first current, a second current, and a third current, wherein the first current is a current flowing through the first winding unit, the second current is a current flowing through the second winding unit, and the third current is a sampled current of the third winding unit;

[0093] Whether there is a phase loss and a phase loss winding unit of the motor is detected according to the first current, the second current, and the third current.

[0094] Among them, all relevant contents of each scenario involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0095] It should be understood that the above-mentioned memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0096] In the embodiment of the present application, the processor of the above-mentioned device may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0097] It should be understood that the "at least one" involved in the embodiments of the present application refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0098] Furthermore, unless otherwise specified, ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects. For example, the first information and the second information are only used to distinguish different information, and do not indicate the difference in content, priority, sending order or importance of the two types of information.

[0099] In the implementation process, each step of the above method can be completed by the integrated logic current of the hardware in the processor or the instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor to be executed, or a combination of hardware and software units in the processor to be executed. The software unit can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor executes the instructions in the memory, and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

[0100] An embodiment of the present application also provides a medical device having the above-mentioned control unit or ventricular assist device.

[0101] An embodiment of the present application also provides a computer storage medium, wherein the computer storage medium stores a computer program for electronic data exchange, and the computer program enables a computer to execute part or all of the steps of any method recorded in the above method embodiments.

[0102] The present application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute some or all of the steps of any method described in the above method embodiment. The computer program product may be a software installation package.

[0103] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0104] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0105] In the several embodiments provided in the present application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the above-mentioned units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0106] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0107] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0108] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or all or part of the technical solution, can be embodied in the form of a software product, which is stored in a memory and includes several instructions for a computer device (which can be a personal computer, server or TRP, etc.) to execute all or part of the steps of the various embodiments of the present application. The aforementioned memory includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0109] A person skilled in the art may understand that all or part of the steps in the various methods of the above embodiments may be completed by instructing the relevant hardware through a program, and the program may be stored in a computer-readable memory, which may include a flash drive, ROM, RAM, a magnetic disk or an optical disk, etc.

[0110] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A motor fault detection method, characterized in that: Applied to a ventricular assist device, the ventricular assist device comprises an impeller, a motor for driving the impeller to rotate, and a control unit for controlling the motor, the motor comprises a three-phase winding, the three-phase winding comprises a first winding unit, a second winding unit, and a third winding unit; the method comprises: Before starting the motor, applying an excitation signal to the first winding unit; Obtaining a first current, a second current, and a third current, wherein the first current is a current flowing through the first winding unit, the second current is a current flowing through the second winding unit, and the third current is a current flowing through the third winding unit; Whether there is a phase loss and a phase loss winding unit of the motor is detected according to the first current, the second current, and the third current.

2. The method according to claim 1, characterized in that The method of detecting whether the motor has a phase loss and a phase loss winding unit according to the first current, the second current and the third current includes: respectively comparing the first current, the second current and the third current with a preset current; If the first current, the second current and the third current are all greater than the preset current, it is determined that the motor does not have a phase loss; If any one of the first current, the second current and the third current is less than or equal to the preset current, it is determined that the motor has a phase loss, and the phase-missing winding unit is determined based on the number of the first current, the second current and the third current that are less than or equal to the preset current.

3. The method according to claim 2, characterized in that The determining the missing-phase winding unit according to the number of the first current, the second current, and the third current that is less than or equal to the preset current includes: If the first current, the second current and the third current are all less than or equal to the preset current, it is determined that the first winding unit is the missing-phase winding unit, or the second winding unit and the third winding unit are the missing-phase winding units; If the second current is less than or equal to the preset current, and the first current and the third current are greater than the preset current, determining that the second winding unit is the missing-phase winding unit; If the third current is less than or equal to the preset current, and the first current and the second current are greater than the preset current, it is determined that the third winding unit is the missing-phase winding unit.

4. The method according to claim 1, characterized in that: The motor includes a first stator, a first rotor, a second stator, a second rotor and a rotating shaft, the first rotor and the second rotor are fixed to the rotating shaft, the first stator drives the first rotor, and the second stator drives the second rotor; the method further includes: During the operation of the motor, detecting whether the first stator has a phase loss; If it is detected that the first stator has a phase loss, a target rotation speed is obtained, and the target rotation speed is a preset rotation speed of the ventricular assist device.

5. The method according to claim 4, characterized in that The method further comprises: If the target speed is less than or equal to m times the maximum speed, stop supplying current to the first stator, the maximum speed is the maximum speed allowed by the ventricular assist device, and m is greater than 0 and less than 1; determining a target torque according to the target speed; A target current is increased according to the target torque, the target current being a current flowing through the second stator.

6. The method according to claim 5, characterized in that The detecting whether the first stator has a phase loss includes: Acquire a plurality of sampled currents, where the sampled currents are currents collected flowing through the winding unit in the first stator; If it is detected that the target sampling current is less than or equal to the target threshold, it is determined that the first stator has a phase loss, and the target sampling current is any one of the multiple sampling currents; Otherwise, it is determined that there is no phase loss in the first stator.

7. The method according to claim 4, characterized in that The method further comprises: If the target speed is greater than m times the maximum speed, an electrical angle set is obtained, where the electrical angle set is a set of electrical angles of the rotational torque generated by each winding unit in the second stator; The currents flowing through each phase winding unit in the first stator and the second stator are respectively controlled according to the electrical angle set, so that the first rotor and the second rotor rotate synchronously.

8. A control unit for a ventricular assist device, characterized in that: The ventricular assist device comprises an impeller, a motor for driving the impeller to rotate, and a control unit for controlling the motor, wherein the motor comprises a three-phase winding, wherein the three-phase winding comprises a first winding unit, a second winding unit, and a third winding unit; and the control unit comprises one or more processing units, wherein the one or more processing units are used to: Before starting the motor, applying an excitation signal to the first winding unit; Obtaining a first current, a second current, and a third current, wherein the first current is a current flowing through the first winding unit, the second current is a current flowing through the second winding unit, and the third current is a current flowing through the third winding unit; Whether there is a phase loss and a phase loss winding unit of the motor is detected according to the first current, the second current, and the third current.

9. A ventricular assist device, characterized in that: The ventricular assist device comprises: impeller; A motor driving the impeller to rotate, the motor comprising a three-phase winding, the three-phase winding comprising a first winding unit, a second winding unit and a third winding unit; A control unit for controlling the motor, wherein the control unit is used to execute the steps in the method according to any one of claims 1 to 7.

10. A medical device, characterized in that: The method comprises a processor, a memory and a communication interface, wherein the memory stores one or more programs, and the one or more programs are executed by the processor, and the one or more programs include instructions for executing the steps in the method according to any one of claims 1 to 7.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute the steps of the method according to any one of claims 1 to 7.

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