RU2525300C1 - Method to control three-phase valve electric motor of implanted rotary electric pump of cardioprosthesis with provision of liveness property (versions) - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: by a signal from current sensors, a failure is detected in a chain of one of three phases of an anchor winding. Then by means of a microcontroller device a signal is sent for actuation of a protective element of the failed phase, the process of automatic switching of two operating phases is carried out, providing for development of a motor torque. The protective element is represented by power switches of that inverter stand, to which the failed phase is connected. Remaining switches, forming a single-phase bridge inverter, are switched by means of a microcontroller device, carrying out serial selection of previously recorded control codes from memory cells corresponding to the condition of the anchor winding and position of the rotor. The criterion of available fault, as well as sound and light signals announcing the available fault and time of its occurrence, are generated by means of the microcontroller.

EFFECT: development of the method to control a three-phase valve electric motor of an implanted rotary electric pump of a cardioprosthesis with provision of liveness property, which provides for realisation of liveness property of a three-phase valve electric motor, comprising one three-phase bridge inverter and having only three outputs from an anchor winding connected as star.

2 cl, 6 dwg, 2 tbl

Description

FIELD OF TECHNOLOGY

The invention relates to the field of electric devices and mechanisms requiring quality assurance of increased survivability, in particular to the field of control of a three-phase valve electric motor of implantable electric blood pumps.

BACKGROUND

It is known [1] that about 7% of failures of implantable electric pumps occur due to the breakage of wires supplying power to the armature winding of the electric pump motor inside the patient. The elimination of such a failure is possible only by operational replacement of the failed pump with a working pump. The time elapsing from the moment a failure is detected to the patient’s delivery for replacement surgery leaves him no chance of survival. In this regard, ensuring the survivability of the electric pump is an urgent task. If, despite the interruption of the phase, the engine continues to rotate the pump, then there is enough time after receiving an interruption signal to prepare for the implant replacement operation.

A known method of controlling a three-phase valve motor - a valve actuator - providing survivability [2], which monitors the signals of current sensors included in each phase, and in the absence of current in one phase, it is turned off from the circuit by burning a fuse inserted between the source power supply and phase winding. The two remaining operational phases independently commute in accordance with the signals of the rotor position sensor, forming alternately several positions of the magnetomotive force vector — the MDS of the armature in space, followed by the rotor, continuing to rotate. To implement the control method according to the method [2], three independent single-phase bridge circuits of the switch were installed in the power electronic converter of the valve motor, each of which included one phase of a three-phase armature winding and a protective element in the form of a fusible insert.

However, in the control method according to the invention [2], it is necessary to derive from the three-phase armature winding all six terminals - both the beginning and the ends of each phase, which makes it difficult to conduct wire communication between the electromechanical transducer located inside the patient and the electronic unit installed externally due to increase the overall cross section of the cable. In addition, the presence of a fusible insert and a device for burning it when a failure is detected complicates the hardware.

There is also known a method of controlling a valve motor with providing survivability properties [3], which consists in the fact that at each interval of pulse-width modulation, the operational state of each of the three phases is diagnosed and, if a failure is detected in one of the phases, the microcontroller control system changes the task the formation of phase currents of the remaining phases in such a way as to ensure continued rotation of the motor rotor. The disadvantages [3] include a rather complicated control scheme, which is necessary for processing the algorithm for restoring engine operability in case of failure in one of the three single-phase power switch cells, the increased complexity of the control algorithm, and the presence of six conclusions from the three-phase armature winding.

Closest to the claimed invention, according to the greatest number of similar features, is a control method in which a control microcontroller [4] is used for implementation, which generates control signals based on the processing of information received from the rotor position sensor, current sensors and rotational speed setter into it a program control algorithm, so that the phase of the currents remains unchanged, and the amplitude changes according to the given law laid down in the program.

The disadvantages of the invention [4] include the need to output twice as many conclusions from the armature winding, as well as the fact that the microcontroller not only uses predefined amplitude values of the generated phase currents, but also calculates the control action in the control process, which significantly reduces the speed of the system.

There is a need to create such a method for controlling a three-phase valve electric motor of an implantable rotational cardioprosthesis electric pump, which would ensure the implementation of the survivability property of a three-phase valve electric motor, containing one three-phase bridge inverter and having only three leads from the armature winding connected by a star circuit.

The technical result to which the proposed invention is directed is the creation of such a method for controlling a three-phase valve electric motor of an implantable rotary cardioprosthesis rotary electric pump with ensuring the survivability property, which would ensure the implementation of the survivability property of a three-phase valve electric motor containing one three-phase bridge inverter and having only three leads from the armature winding connected by a star pattern.

SUMMARY OF THE INVENTION

The specified technical result is achieved by the fact that a method for controlling a three-phase valve electric motor of an implantable rotary cardioprosthesis rotary electric pump is provided, ensuring the survivability property, which consists in the fact that a signal from the current sensors reveals a failure in the circuit of one of the three phases of the armature winding connected by a star circuit, then , to ensure the survivability properties, by means of a microcontroller control device, a signal is issued for the protective element of the failed phase to operate, the process a current switching of the working two phases, ensuring the creation of the motor torque, and as a protective element, use the power switches of the rack of the three-phase bridge inverter of the valve electric motor to which the failed phase is connected, and the rest of the keys forming a single-phase bridge inverter are switched by means of a microcontroller control device selection of pre-recorded control codes from the corresponding state of the armature winding and the position of the rotor of the memory cells and.

A method for controlling a three-phase valve electric motor of an implantable rotary cardioprosthesis rotary electric pump is also proposed, ensuring the survivability property, in which, if one of the phases fails, the control signals generated by the microcontroller are used and they are controlled by a single-phase bridge inverter, the diagonal of which includes two operable remaining connected in series phase so that the three-phase valve motor with a rotating magnetic field, in the event of a failure in the circuit of one of the phases, they are converted into a single-phase motor with a pulsating field, which ensures the survivability property in the event of a malfunction, which, if necessary, among other things, supports auxiliary blood circulation, while there is a sign of a malfunction, as well as sound and light signals indicating the presence of the malfunction and the time of its occurrence are produced by means of a microcontroller, in addition, by the presence of only three leads from the winding, they provide a small cross-section of the wiring harness emerging from the implant to the outside, while ementa uses power switches of the three-phase bridge inverter rack BLDC motor, which is connected to the failed phase, and the remaining keys, which form a single-phase bridge inverter commute by microcontroller control device for a given process, which ensures the creation of a pulsating magnetomotive force vector in accordance with rotor position.

According to the invention, power switches of the rack of a three-phase bridge inverter of a valve electric motor to which a failed phase is connected are used as a protective element, and the remaining keys forming a single-phase bridge inverter are switched by means of a microcontroller control device according to a preset process recorded in memory that ensures the creation of a pulsating vector MDS, in accordance with the position of the rotor. In other words, the proposed method is based on ensuring the survivability of a three-phase valve electric motor of an implantable cardioprosthesis pump in the event of a circuit failure in one of the phases by using the control signals generated by a single-phase bridge inverter generated and stored in the microcontroller's memory, the diagonal of which includes two working phases connected in series that are still operational.

In contrast to the known methods in which the protective element disconnects the entire failed electrical circuit, including the phase of the armature winding and the inverter power switches connected to it, and for this each phase has its own individual single-phase inverter, the proposed control method essentially turns a three-phase valve motor with a rotating magnetic field, in the event of a failure in the circuit of one of the phases, into a single-phase motor with a pulsating field, thereby ensuring the survivability property in case of such a malfunction, while the microcontrol Weller generates an indication of a failure, as well as sound and light signals notifying the presence of the fault and the time of its occurrence. Due to the fact that the engine continues to work, there is a margin of time for preparing a new, working copy and replacing the implantable device. In addition, the presence of only three leads from the winding provides a small cross-section of the wiring harness extending outward from the implant.

Figure 1 presents a functional diagram of a three-phase valve motor, where

EMF - electromechanical energy converter, structurally combined with a pump,

SK - power switch,

BDT - block of current sensors,

Akb - rechargeable battery,

LED - LED

SR - siren,

UMK - control microcontroller,

CPE is the central processor element,

RAM and ROM - storage devices, operational and permanent, respectively,

Reg. PWM - built-in regulators, including those with pulse-width modulation, output port - the port from which control actions are output, input port - port for inputting information from sensors.

The implantable element is an electromechanical energy converter - EMF with a built-in pump. The power to its winding is anchored by a bundle of three power wires from the power switch - SC, made according to the scheme of a three-phase bridge frequency-controlled inverter. SC control is carried out from a microcontroller, the input port of which receives signals from three current sensors - BDT in the phases of the electromagnetic field and a speed reference signal. The signal about the position of the rotor is generated during vector control by performing calculations in the processor according to the vector diagram of the engine. The primary autonomous source of power is the battery - battery. LED - LED and siren - SR are used as signaling devices.

Figure 2 shows a simplified schematic diagram of a power switch indicating, for definiteness, key numbers - 1, 2, 3, 4, 5, 6 and a diagram of a three-phase winding of an EMF armature connected to it with phase designations A, B, C. The voltage of the power source is indicated = Uп.

Figure 3, where

F1 and F2 - the initial and final position of the axis of the rotor when the MDS vector is in position F1,

F1, F2, F3, F4, F5, F6 - six consecutive positions of the MDS vector, a spatial diagram of six consecutive positions of the MDS vector created by the armature winding during auto-switching and two positions of the rotor flux vector during three-phase operation is presented.

Figure 4, where

F1, F2, F3, F4, F5, F6 - six consecutive positions of the axis of the rotor, fixed by the position sensor,

F1 and F2 are two consecutive positions of the MDS vector,

a diagram of two positions of the MDS vector of the anchor and six positions of the rotor flux vector with an open circuit in the phase C circuit is presented.

In Fig 5, where

U _A , U _B , U _C - phase voltage

U _AB , U _AC , U _BC - line voltage

T is the period

time diagrams are given: three channels of the device for generating a code on the current position of the EMF rotor - three upper graphs, operation of power switches SK - six subsequent graphs, as well as linear and phase voltages of the armature winding during three-phase operation of the valve motor in the absence of an open circuit in one of the phases .

6, where

U _A , U _B , U _C - phase voltage

U _AB , U _AC , U _BC - line voltage

T is the period

the time diagrams of signals about the position of the rotor are presented — the three upper graphs, the operation of the power switches — six subsequent graphs, the linear and phase voltages of the armature winding in the event of an open circuit in one of the phases — in the phase C circuit, see FIG. 2.

Table 1 also presents the unique correspondence of the output codes of the microcontroller that control the power keys of the SC to codes characterizing the spatial position of the rotor for a three-phase operation mode.

Table 2 shows the correspondence of control codes generated by MK according to the present invention when one of the phases - phase C of the armature of the armature of the EMF breaks in the circuit.

The invention is implemented as follows. In the absence of breaks in the armature winding circuits, in other words, during normal three-phase operation of the valve motor, the MK generates double-byte codes, which are the addresses of the memory cells in which the predetermined control codes are stored in the electrical circuit diagram. The high byte of the address code contains in its low nibble the code generated by current sensors. In particular, the absence of an open in the phase circuit corresponds to a logical unit in a certain category of current sensor code. Thus, binary - In code 0111 in the lower nibble of an address, there are no breaks in the circuits of all three phases. And this code refers to the memory area in which six control codes are stored for the implementation of auto-switching under normal three-phase mode. The smallest nibble of the address contains a code characterizing the current position of the rotor, obtained by calculation in the processor using equations describing the vector diagram - vector control.

Thus, for example, as shown in Fig. 5, the binary decimal code - BCD address 8704 means that there are no breaks - the least nibble of the high byte 7B = 0111BCD, and the rotor is in the spatial position, which corresponds to the code 04B = 0000 0100BCD. From the memory cell with this address, the contents — the control binary code 00100100B — are set to the output port and, in accordance with it, the keys 3 and 6 of the IC shown in FIG. 2 are closed, the current flows through phases A and C, providing such a position of the MDC vector with respect to to the current position of the rotor, at which a torque of the desired direction is created.

When the rotor is rotated to the position at which the code will change, the address will change and a new control code will arrive at the output port from the cell with this address. The switching process occurs in accordance with Table 1.

According to the proposed method, the control process is supplemented by a polling cycle of current sensors and sending the results of this survey to different memory areas storing control codes. As mentioned above, if the result of the survey of current sensors gives the code 0111B, then the memory area is determined by the high byte in binary decimal code, for example 87BCD.

If one of the phases of the armature winding breaks in the circuit, the code will change in the polling cycle of current sensors. For example, if the phase C circuit breaks in the polling cycle, the code 0110V will be received. This code arrives as the lower nibble of the high byte of the address and sends to another memory area, which stores other control codes corresponding to the same codes characterizing the current position of the rotor, as shown in Table 2. Two bits of the control code associated with the power keys of the phase C, contain a logical zero and disconnect the rack of the three-phase inverter, to which phase C is connected, and 4 bits of the control code ensure the operation of the single-phase bridge inverter, formed by the remaining two racks, to the cat The correct phases A and B of the armature winding are connected.

Two more memory areas are organized in the same way, corresponding to cases of a break in the phase A circuit and in the phase B circuit. And they are accessed using the code obtained in the current sensor polling cycle.

Thus, the proposed control method provides the organization of the process of polling current sensors, and also provides for the allocation of four memory areas and recording in each of them the corresponding control codes, pre-compiled in accordance with the actual electrical circuit of the armature winding circuit and the necessary law of the formation of torque in the presence of this scheme.

When switching from a three-phase mode of operation to a single-phase mode, the torque will decrease, which at the same moment of load will reduce the speed. To restore it to its previous value, it is necessary to use a comparison of the current frequency with a given frequency and an increase in the duty cycle of the digital PWM built into the MC or the supply voltage.

Each time a code appears in the polling cycle of current sensors that differs from code 0111B, indicating a malfunction and preventing failure due to the application of the proposed control method, the MK generates signals supplied to the corresponding actuators - LED and siren, which are light and sound notification of a malfunction and the need to prepare for an implant replacement operation. The system also provides for turning off the sound signal. But the light does not turn off.

In the present invention, the method of controlling a three-phase valve electric motor allows providing survivability property in the presence of only a three-phase bridge inverter with six power switches and three wires connecting it with the armature winding of the electromechanical converter located in the patient.

Thus, a technical result has been achieved by creating such a method for controlling a three-phase valve electric motor of an implantable rotary cardioprosthesis rotary electric pump with ensuring the survivability property, which provides the survivability property of a three-phase valve electric motor containing one three-phase bridge inverter and having only three conclusions from the armature winding connected according to the star circuit ".

INDUSTRIAL APPLICABILITY

The proposed variants of the invention relate mainly to three-phase valve electric motors of devices and mechanisms requiring quality assurance of increased survivability, in particular to the field of control of a three-phase valve electric motor of implantable electric blood pumps.

Variants of such a method for controlling a three-phase valve electric motor of an implantable rotary cardioprosthesis rotary electric pump with the provision of survivability properties are provided, which ensures the implementation of the survivability property of a three-phase valve electric motor containing one three-phase bridge inverter and having only three conclusions from the armature winding connected according to the star circuit.

A method of controlling a three-phase valve electric motor with the survivability property can be used not only to drive an implantable rotary electric pump, but also where the failure to operate for a fraction of a few hours can lead to disruption of the safe operation of the equipment with a risk to personnel, leading to significant economic losses during accidents at maintenance-free facilities with a non-stop or long cycle of work, for example, in the drive of technological centrifuges and separators.

Thus, the invention is industrially applicable and can be widely used in the field of electric drive devices and mechanisms requiring quality assurance of increased survivability, in particular to the field of control of a three-phase valve electric motor of implantable electric pumps.

INFORMATION SOURCES

1. Evgenij v. Potapov Friedrich Kaufmann Alexander Stepanenko Ewald Hening Juliane Vierecke Alexandra Löw Elke Lehmkuhl Nikolay Dranishnikov Roland Hetzer and Thomas Krabatsch ASAIOJournal. 58 (6): 578-582, 2012.

2. RF patent No. 2447561, IPC Н02Н 7/09, publ. 04/10/2012.

3. A.S. USSR No. 1746482, MKI 3 Н02Р 7/42, publ. In BI, 1992, No. 25.

4. RF patent No. 2311721, IPC Н02Р 6/12; Н02Р 6/16, publ. 11/27/2007.

Table 1 BCD code rotor position and fault Code B rotor position and phase status (malfunction) Control Code B 8705 1000011100000101 00 000110 8704 1000011100000100 00 100 100 8706 1000011100000110 00 100001 8702 1000011100000010 00 001001 8703 1000011100000011 00 011000 8701 1000011100000001 00 010010

table 2 BCD code rotor position and fault Code B rotor position and phase status (malfunction) Control Code B 8705 1000011100000101 00 000110 8704 1000011100000100 00 000110 8706 1000011100000110 00 001001 8702 1000011100000010 00 001001 8703 1000011100000011 00 001001 8701 1000011100000001 00 000110

Claims (2)

1. A method for controlling a three-phase valve electric motor of an implantable rotational cardioprosthesis electric pump with the survivability property, which consists in the fact that a signal from the current sensors reveals a failure in the circuit of one of the three phases of the armature winding connected by a star circuit, then, to ensure the survivability property, by means of a microcontroller control device, they signal the operation of the protective element of the failed phase, the process of automatic switching of the working two phases is carried out, ensuring the creation of a rotation the current moment of the engine, moreover, the power keys of the rack of the three-phase bridge inverter of the valve electric motor to which the failed phase is connected are used as the protective element, and the remaining keys forming the single-phase bridge inverter are switched by the microcontroller control device, sequentially selecting pre-recorded control codes from the corresponding the state of the armature winding and the position of the rotor of the memory cells. 2. A method for controlling a three-phase valve electric motor of an implantable rotational cardioprosthesis electric pump with a survivability property, in which, if a circuit of one of the phases fails, the control signals generated by the single-phase bridge inverter are formed and stored in the microcontroller’s memory, the diagonal of which includes two working phases connected in series so that a three-phase valve motor with a rotating magnetic field, in case of failure in the circuit of one of the phases, is converted into a non-phase motor with a pulsating field, which ensures the survivability property in case of a malfunction, which, if necessary, among other things, supports auxiliary circulation, while a sign of a malfunction, as well as sound and light signals that indicate the presence of a malfunction and the time of its occurrence, produce through the microcontroller, in addition, the presence of only three leads from the winding provides a small cross-section of the wiring harness exiting from the implant to the outside, while using as a protective element power keys of the rack of the three-phase bridge inverter of the valve electric motor to which the failed phase is connected, and the other keys forming the single-phase bridge inverter are switched by means of a microcontroller control device according to a predetermined process that ensures the creation of a pulsating vector of the magnetomotive force, in accordance with the position of the rotor.

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