Energy consumption braking reverse rotation preventing device and method for permanent magnet motor direct-driven electric submersible centrifugal pump

Abstract

The invention relates to the field of mechanical oil extraction of oil fields, and discloses an energy consumption braking anti-reverse device and method for an electric submersible centrifugal pump directly driven by a permanent magnet motor. The control cabinet is arranged on the ground, is connected with the permanent magnet synchronous motor in the submersible permanent magnet motor direct-drive electric submersible centrifugal pump oil extraction system through a cable, and can monitor and respond to the working state of the permanent magnet synchronous motor in real time, so that the permanent magnet synchronous motor drives the electric submersible centrifugal pump to work; an energy consumption braking circuit and a motor monitoring protection circuit are arranged in the control cabinet; the motor monitoring protection circuit is used for monitoring and responding to the working state of the permanent magnet synchronous motor in real time; the energy consumption braking circuit is used for being connected when the permanent magnet synchronous motor loses power and consuming reverse electric energy generated by the permanent magnet synchronous motor in time when the permanent magnet synchronous motor rotates reversely. The problem that the service life of the motor is shortened due to the fact that electric energy generated by reverse rotation of the permanent magnet motor under the power-off condition is converted into heat energy to be consumed in the motor can be effectively prevented.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield mechanical oil production, and in particular to an energy-consuming braking anti-reversal device and method for a permanent magnet motor directly driven electric submersible centrifugal pump. Background Art

[0002] During normal operation of the system, the submersible centrifugal pump transports crude oil from the bottom of the well to the wellhead through centrifugal force. However, during operation, if the oil production system suddenly loses power, the crude oil in the oil pipe will flow back under the action of gravity, causing the centrifugal pump impeller and the permanent magnet motor rotor to rotate in the opposite direction at high speed. In this case, the permanent magnet motor can be regarded as a power generation device. The rotation of the permanent magnet rotor generates an induced current in the motor winding, which is eventually consumed in the form of heat energy, causing the internal temperature of the permanent magnet motor to rise, which in turn has an adverse effect on the service life of the motor.

[0003] At present, the existing technologies to prevent the direct drive motor of oil production pump from reversing mainly include ratchet-pawl mechanical anti-reversal technology, hydraulic anti-reversal technology and electromagnetic brake anti-reversal technology. These technologies are mostly used for rod lifting and are usually arranged in surface equipment. They cannot effectively solve the problem of reverse rotation of permanent magnet motor in electric submersible centrifugal pump system when power is lost. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide an energy-consuming braking anti-reverse device and method for a permanent magnet motor directly driven electric submersible centrifugal pump, which can effectively prevent the electric energy generated by the reverse rotation of the permanent magnet motor under power-off conditions from being converted into heat energy and consumed inside the motor, thereby shortening the life of the motor.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an energy-consuming braking anti-reversal device for a permanent magnet motor directly driven electric submersible centrifugal pump, which includes a control cabinet and a cable; the control cabinet is arranged on the ground, and is connected to the permanent magnet synchronous motor in the oil production system of the submersible permanent magnet motor directly driven electric submersible centrifugal pump through a cable, so as to be able to monitor and respond to the working state of the permanent magnet synchronous motor in real time, and then the permanent magnet synchronous motor drives the electric submersible centrifugal pump to work; an energy-consuming braking circuit and a motor monitoring and protection circuit are arranged in the control cabinet; the motor monitoring and protection circuit is used to monitor and respond to the working state of the permanent magnet synchronous motor in real time; the energy-consuming braking circuit is used to be connected when the permanent magnet synchronous motor loses power, and timely consume the reverse electric energy generated by the permanent magnet synchronous motor when the permanent magnet synchronous motor reverses.

[0006] Further, the energy consumption braking circuit includes a rectifier circuit U1, an energy consumption circuit U2, three first energy consumption resistors R1 and an AC contactor normally closed contact KM13;

[0007] The input end of the rectifier circuit U1 is connected to the first energy dissipation resistor R 1The normally closed contact KM13 of the AC contactor is connected in parallel to the PMSM 3; the output end of the rectifier circuit U1 is connected to the energy consumption circuit U2 to consume the reverse electric energy generated by the permanent magnet synchronous motor.

[0008] Further, the rectifier circuit U1 includes six thyristors, namely, a first thyristor S1 to a sixth thyristor S6;

[0009] The first thyristor S1 and the second thyristor S2 are connected in series, and the common end thereof is connected to the first phase winding of the permanent magnet synchronous motor through the first first energy consumption resistor R1 and the normally closed contact KM13 of the AC contactor;

[0010] The third thyristor S3 and the fourth thyristor S4 are connected in series, and the common end thereof is connected to the second phase winding of the permanent magnet synchronous motor through the second first energy consumption resistor R1 and the normally closed contact KM13 of the AC contactor;

[0011] The fifth thyristor S5 and the sixth thyristor S6 are connected in series, and their common end is connected through the third first energy consumption resistor R 1 And the normally closed contact KM13 of the AC contactor is connected to the third phase winding of the permanent magnet synchronous motor.

[0012] Furthermore, the energy consumption circuit U2 includes an insulated gate bipolar transistor VT, a second energy consumption resistor R 2 and supercapacitor C;

[0013] The supercapacitor C is connected in parallel to both ends of the DC bus of the rectifier circuit to store the excess electrical energy generated by the system;

[0014] Insulated gate bipolar transistor VT and second energy dissipation resistor R 2 After being connected in series, they are connected in parallel with the supercapacitor C to consume electrical energy.

[0015] Further, the motor monitoring protection circuit includes a circuit breaker QS, a first fuse FU1, a second fuse FU2, a first thermal relay FR1, a second thermal relay FR2, a second normally open contact KM12 and an AC contactor KM1;

[0016] The three input terminals L1 to L3 of the three-phase AC power of the power supply are respectively connected in series with the circuit breaker QS and the first fuse FU1;

[0017] A first fuse FU1 connected in series with the first input terminal L1 and the second input terminal L2 is respectively connected to two connection terminals of the second normally open contact KM12;

[0018] The first fuse FU1 connected in series with the first input terminal L1 is also connected in series with the second fuse FU2, and the series connection is connected to the first thermal relay FR1 and one end of the AC contactor KM1 in sequence;

[0019] The first fuse FU1 connected in series with the second input terminal L2 is also connected in series with the second fuse FU2. After the series connection, the second fuse FU2 is connected to the other end of the AC contactor KM1.

[0020] The first fuse FU1 connected in series with the third input terminal L3 is connected to a first connection end of the second normally open contact KM12.

[0021] Furthermore, the second normally open contact KM12 is connected to one end of the second thermal relay FR2, and the other end of the second thermal relay FR2 is connected to the permanent magnet synchronous motor through a cable.

[0022] Furthermore, a start button SB1 and a stop button SB2 are provided between the first thermal relay FR1 and the AC contactor KM1; and the start button SB1 and the stop button SB2 are provided on the door of the control cabinet.

[0023] Furthermore, the start button SB1 and the stop button SB2 are connected in series, and a first normally open contact KM11 is connected in parallel to both ends of the start button SB1.

[0024] An energy-consuming braking anti-reversal method based on the above-mentioned energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump comprises: when the permanent magnet synchronous motor is started, the circuit breaker QS is pressed, and then the start button SB1 is pressed, and the three-phase alternating current passes through the first fuse FU1 and the second fuse FU2, so that the AC contactor KM1 is energized, at this time, the first normally open contact KM11 and the second normally open contact KM12 are closed, and the normally closed contact KM13 is disconnected, and the three-phase alternating current passes through Circuit breaker QS, first fuse FU1, second normally open contact KM12, first thermal relay FR1, second thermal relay FR2 enters the permanent magnet synchronous motor, and the motor starts to run normally. At this time, the energy-consuming braking circuit does not consume the power of the main circuit;

[0025] When the power grid is suddenly powered off or the stop button SB2 is pressed, the AC contactor KM1 loses power, the first normally open contact KM11 and the second normally open contact KM12 are disconnected, the normally closed contact KM13 is closed, the permanent magnet synchronous motor is powered off, and the permanent magnet synchronous motor reverses to generate three-phase AC power. The three-phase AC power passes through the normally closed contact KM13 and the first energy consumption resistor R 1 It flows into the rectifier circuit U1, forms direct current after rectification, and enters the energy consumption circuit U2 to consume the electric energy generated by the reversal of the permanent magnet synchronous motor PMSM.

[0026] Furthermore, the permanent magnet synchronous motor reverses to generate three-phase alternating current, and the energy consumption circuit U2 consumes the electric energy generated by the permanent magnet synchronous motor PMSM reverses, including:

[0027] The supercapacitor C is responsible for absorbing the excess electrical energy in the circuit. The first energy consumption resistor R 1 Prevent excessive current from damaging the circuit and consuming some electrical energy;

[0028] When the supercapacitor C reaches the full state, the voltage across its two ends increases, the insulated gate bipolar transistor VT is turned on, and the second energy dissipation resistor R 2 It is connected to the circuit to accelerate the consumption of electric energy and enhance the braking effect of the permanent magnet synchronous motor PMSM until the motor stops reversing.

[0029] The present invention adopts the above technical solution, which has the following advantages:

[0030] 1. The present invention adds an energy-consuming braking circuit U2 to the input busbar of the submersible permanent magnet motor to consume the electric energy generated by the permanent magnet synchronous motor PMSM when it loses power and reverses. This design effectively avoids the problem that the electric energy generated by the permanent magnet synchronous motor PMSM due to power loss and reversal is converted into heat energy and consumed inside the motor, thereby causing the motor to overheat and shorten its service life.

[0031] 2. The present invention controls the access of the energy-consuming braking circuit through the AC contactor KM1, so that it only works when the permanent magnet synchronous motor PMSM loses power, ensuring efficient energy consumption management of the system and avoiding additional power loss during normal operation.

[0032] 3. The present invention accurately controls the second energy dissipation resistor R through the insulated gate bipolar transistor VT 2 The connection and disconnection of the supercapacitor accelerates the energy consumption in the circuit and ensures the rapid release of the energy generated by the motor reversal. This design not only effectively reduces the voltage fluctuation across the supercapacitor C, but also significantly extends the service life of the supercapacitor C.

[0033] 4. The present invention ensures that the permanent magnet synchronous motor PMSM runs smoothly and safely during the reverse braking process after power failure through a reasonably designed energy-consuming braking system, avoids excessive mechanical and electrical stress inside the motor, and improves the reliability and durability of the entire system.

[0034] In summary, the present invention can provide an energy-saving and environmentally friendly oil production system, which can be widely used in the field of oil production. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the overall structure of the energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump in an embodiment of the present invention;

[0036] Figure 2 is a front view of a control cabinet in an embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of a circuit in a control cabinet in an embodiment of the present invention;

[0038] Figure 4 is a schematic diagram of an energy-consuming braking circuit in an embodiment of the present invention;

[0039] Description of reference numerals:

[0040] 1-control cabinet, 2-cable, 3-permanent magnet synchronous motor PMSM, 4-electric submersible centrifugal pump, U1-rectifier circuit, U2-energy consumption circuit, R 1 - first energy consumption resistor, KM13- normally closed contact of AC contactor, S1~S6- first thyristor to sixth thyristor, VT- insulated gate bipolar transistor, R 2 -Second energy consumption resistor, C-super capacitor, QS-circuit breaker, FU1-first fuse, FU2-second fuse, FR1-first thermal relay, FR2-second thermal relay, KM1-AC contactor, KM12-second normally open contact, SB1-start button, SB2-stop button, KM11-first normally open contact. DETAILED DESCRIPTION

[0041] Since the existing submersible permanent magnet motor direct-driven electric submersible centrifugal pump production system lacks an effective anti-reversal device in the power-off state, the energy generated during the motor reversal process is difficult to be effectively processed, thereby affecting the overall performance of the system and the service life of the motor. In order to solve the problem of reverse rotation of the permanent magnet motor in the electric submersible centrifugal pump system when the power is off, the present invention proposes an energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump. The device is installed in a ground control cabinet and connected to the permanent magnet synchronous motor through a cable to ensure that the device can monitor and respond to the working state of the motor in real time. The energy-consuming braking device is controlled by an AC contactor to achieve its access when the permanent magnet synchronous motor loses power, and consumes the reverse electric energy generated by the motor in time when the motor reverses, thereby avoiding excessive heat energy generated inside the motor. Through the control of an insulated gate bipolar transistor (IGBT), the device can accurately control the access and disconnection of the energy-consuming braking resistor, ensure the stability of the motor braking process and the effective consumption of electric energy, so as to effectively avoid energy loss and temperature rise caused by motor reversal, and improve the safety and reliability of the system.

[0042] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0044] In one embodiment of the present invention, an energy-consuming braking anti-reversal device for a permanent magnet motor directly driven electric submersible centrifugal pump is provided to prevent the permanent magnet motor from reversing in the event of a power outage, thereby improving the operating stability of the system and the service life of the equipment. Figures 1 to 4 As shown, the device comprises: a control cabinet 1 and a cable 2;

[0045] The control cabinet 1 is arranged on the ground and connected to the permanent magnet synchronous motor (PMSM) 3 in the oil production system of the submersible permanent magnet motor directly driven electric submersible centrifugal pump through the cable 2, so as to monitor and respond to the working state of the PMSM 3 in real time, and then the PMSM 3 drives the electric submersible centrifugal pump 4 to work;

[0046] The control cabinet 1 is provided with an energy consumption braking circuit and a motor monitoring protection circuit; the motor monitoring protection circuit is used to realize The energy consumption braking circuit is used to be connected when the permanent magnet synchronous motor 3 loses power, and consumes the reverse electric energy generated by the permanent magnet synchronous motor 3 in time when the permanent magnet synchronous motor 3 reverses.

[0047] In a preferred embodiment, Figure 3 , Figure 4 As shown, the energy consumption braking circuit includes a rectifier circuit U1, an energy consumption circuit U2, and three first energy consumption resistors R 1 And the normally closed contact KM13 of the AC contactor. The input end of the rectifier circuit U1 is connected through three first energy consumption resistors R 1 The normally closed contact KM13 of the AC contactor is connected in parallel to the PMSM 3; the output end of the rectifier circuit U1 is connected to the energy consumption circuit U2 to consume the reverse electric energy generated by the PMSM 3.

[0048] In this embodiment, the rectifier circuit U1 includes six thyristors, namely the first thyristor S1 to the sixth thyristor S6. The first thyristor S1 is connected in series with the second thyristor S2, and the common end thereof is connected through the first energy consumption resistor R 1 The normally closed contact KM13 of the AC contactor is connected to the first phase winding of the permanent magnet synchronous motor PMSM 3. Similarly, the third thyristor S3 and the fourth thyristor S4 are connected in series, and their common end is connected through the second first energy consumption resistor R 1The AC contactor normally closed contact KM13 is connected to the second phase winding of the permanent magnet synchronous motor PMSM 3; the fifth thyristor S5 and the sixth thyristor S6 are connected in series, and their common end is connected through the third first energy consumption resistor R 1 And the normally closed contact KM13 of the AC contactor is connected to the third phase winding of the permanent magnet synchronous motor PMSM 3.

[0049] In this embodiment, the energy consumption circuit U2 includes an insulated gate bipolar transistor VT, a second energy consumption resistor R 2 and super capacitor C. The super capacitor C is connected in parallel to both ends of the DC bus of the rectifier circuit to store the excess electric energy generated by the system; the insulated gate bipolar transistor VT and the second energy consumption resistor R 2 After being connected in series, they are connected in parallel with the supercapacitor C to achieve effective consumption of electric energy and avoid overheating inside the permanent magnet synchronous motor PMSM 3.

[0050] When in use, the connection of the dynamic braking circuit is controlled by the normally closed contact KM13 of the AC contactor. When the normally closed contact KM13 is disconnected, the dynamic braking circuit does not consume the electric energy of the main circuit; when the normally closed contact KM13 is closed, the dynamic braking circuit is connected to the main circuit to consume the electric energy generated by the reverse rotation of the permanent magnet synchronous motor PMSM 3.

[0051] In a preferred embodiment, the motor monitoring protection circuit includes a circuit breaker QS, a first fuse FU1, a second fuse FU2, a first thermal relay FR1, a second thermal relay FR2, a second normally open contact KM12 and an AC contactor KM1. The three input terminals L1 to L3 of the three-phase AC power of the power supply are respectively connected in series with the circuit breaker QS and the first fuse FU1. Among them, the first fuse FU1 connected in series with the first input terminal L1 and the second input terminal L2 is respectively connected to two connection ends in the second normally open contact KM12. The first fuse FU1 connected in series with the first input terminal L1 is also connected in series with the second fuse FU2, and after the series connection, it is connected to the first thermal relay FR1 and one end of the AC contactor KM1 in turn; the first fuse FU1 connected in series with the second input terminal L2 is also connected in series with the second fuse FU2, and after the series connection, the second fuse FU2 is connected to the other end of the AC contactor KM1. The first fuse FU1 connected in series with the third input terminal L3 is connected to the first connection end in the second normally open contact KM12.

[0052] In this embodiment, the second normally open contact KM12 is connected to one end of the second thermal relay FR2, and the other end of the second thermal relay FR2 is connected to the permanent magnet synchronous motor PMSM 3 through a cable. By connecting the second normally open contact KM12 of the AC contactor KM1 between the first fuse FU1 and the second thermal relay FR2, the second thermal relay FR2 is connected to the permanent magnet synchronous motor PMSM 3 through a cable, thereby ensuring the safe operation of the motor.

[0053] In this embodiment, a start button SB1 and a stop button SB2 are provided between the first thermal relay FR1 and the AC contactor KM1; and the start button SB1 and the stop button SB2 are provided on the door of the control cabinet 1 (such as Figure 2 ), which is used to control the start and stop operation of the permanent magnet synchronous motor PMSM 3.

[0054] Specifically, the start button SB1 and the stop button SB2 are connected in series, and the first normally open contact KM11 is connected in parallel at both ends of the start button SB1, which is used to close the circuit when the permanent magnet synchronous motor PMSM3 is started. One end of the stop button SB2 is connected to the first thermal relay FR1, and the other end of the stop button SB2 is connected to the AC contactor KM1 via the start button SB1.

[0055] In one embodiment of the present invention, a method for energy-consuming braking and anti-reversal for a permanent magnet motor directly driven electric submersible centrifugal pump is provided, and the method is implemented based on the energy-consuming braking and anti-reversal device for a permanent magnet motor directly driven electric submersible centrifugal pump in the above embodiments. Specifically, in this embodiment, the method includes the following steps:

[0056] 1) When the permanent magnet synchronous motor PMSM 3 is started, the circuit breaker QS is first pressed, and then the start button SB1 is pressed. The three-phase AC power passes through the first fuse FU1 and the second fuse FU2, so that the AC contactor KM1 is energized. At this time, the first normally open contact KM11 and the second normally open contact KM12 are closed, and the normally closed contact KM13 is disconnected. The three-phase AC power passes through the circuit breaker QS, the first fuse FU1, the second normally open contact KM12, and the second thermal relay FR2 into the permanent magnet synchronous motor PMSM 3, and the motor starts to run normally. At this time, the energy-consuming braking circuit does not consume the electric energy of the main circuit.

[0057] 2) When the power grid suddenly loses power or the stop button SB2 is pressed, the AC contactor KM1 loses power, the first normally open contact KM11 and the second normally open contact KM12 are disconnected, the normally closed contact KM13 is closed, and the permanent magnet synchronous motor PMSM 3 is powered off. Due to the pressure difference between the oil and the jacket, the liquid column in the tube generates a backflow, causing the permanent magnet synchronous motor PMSM 3 to reverse, and thus generating three-phase AC in the motor winding. The three-phase AC passes through the normally closed contact KM13 and the first energy dissipation resistor R 1 It flows into the rectifier circuit U1, forms direct current after rectification, and enters the energy consumption circuit U2 to consume the electric energy generated by the reversal of the permanent magnet synchronous motor PMSM.

[0058] In the above step 2), in the process of consuming electric energy, the super capacitor C is responsible for absorbing the excess electric energy in the circuit. 1Prevent excessive current from damaging the circuit and consuming some electrical energy. When the supercapacitor C reaches a full charge state, the voltage across its two ends increases, the insulated gate bipolar transistor VT turns on, and the second energy consumption resistor R 2 It is connected to the circuit to accelerate the consumption of electric energy and enhance the braking effect of the permanent magnet synchronous motor PMSM until the motor stops reversing.

[0059] In summary, the present invention has a reasonable structure and can effectively prevent the problem that the electric energy generated by the reverse rotation of the permanent magnet motor under power-off conditions is converted into heat energy and consumed inside the motor, thereby shortening the life of the motor.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An energy-consuming braking anti-reversal device for a permanent magnet motor directly driven electric submersible centrifugal pump, characterized in that: Including control cabinet and cables; The control cabinet is set on the ground and connected to the permanent magnet synchronous motor in the oil production system of the submersible permanent magnet motor directly driven electric submersible centrifugal pump through cables, so as to monitor and respond to the working state of the permanent magnet synchronous motor in real time, and then the permanent magnet synchronous motor drives the electric submersible centrifugal pump to work; The control cabinet is equipped with an energy-consuming braking circuit and a motor monitoring and protection circuit; The motor monitoring and protection circuit is used to monitor and respond to the working status of the permanent magnet synchronous motor in real time; the energy consumption braking circuit is used to connect when the permanent magnet synchronous motor loses power, and consume the reverse electric energy generated by the permanent magnet synchronous motor in time when it reverses.

2. The energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump according to claim 1, characterized in that: The energy consumption braking circuit includes a rectifier circuit U1, an energy consumption circuit U2, three first energy consumption resistors R1 and an AC contactor normally closed contact KM13; The input end of the rectifier circuit U1 is connected in parallel to the PMSM 3 via three first energy consumption resistors R1 and the normally closed contact KM13 of the AC contactor; the output end of the rectifier circuit U1 is connected to the energy consumption circuit U2 to consume the reverse electric energy generated by the permanent magnet synchronous motor.

3. The energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump as claimed in claim 2, characterized in that: The rectifier circuit U1 includes six thyristors, namely, the first thyristor S1 to the sixth thyristor S6; The first thyristor S1 and the second thyristor S2 are connected in series, and the common end thereof is connected to the first phase winding of the permanent magnet synchronous motor through the first first energy consumption resistor R1 and the normally closed contact KM13 of the AC contactor; The third thyristor S3 and the fourth thyristor S4 are connected in series, and the common end thereof is connected to the second phase winding of the permanent magnet synchronous motor through the second first energy consumption resistor R1 and the normally closed contact KM13 of the AC contactor; The fifth thyristor S5 and the sixth thyristor S6 are connected in series, and the common end thereof is connected to the third phase winding of the permanent magnet synchronous motor through the third first energy consumption resistor R1 and the normally closed contact KM13 of the AC contactor.

4. The energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump as claimed in claim 2, characterized in that: The energy consumption circuit U2 includes an insulated gate bipolar transistor VT, a second energy consumption resistor R2 and a super capacitor C; The supercapacitor C is connected in parallel to both ends of the DC bus of the rectifier circuit to store the excess electrical energy generated by the system; The insulated gate bipolar transistor VT is connected in series with the second energy consumption resistor R2 and then connected in parallel with the super capacitor C to consume electrical energy.

5. The energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump according to claim 1, characterized in that: The motor monitoring protection circuit includes a circuit breaker QS, a first fuse FU1, a second fuse FU2, a first thermal relay FR1, a second thermal relay FR2, a second normally open contact KM12 and an AC contactor KM1; The three input terminals L1 to L3 of the three-phase AC power of the power supply are respectively connected in series with the circuit breaker QS and the first fuse FU1; A first fuse FU1 connected in series with the first input terminal L1 and the second input terminal L2 is respectively connected to two connection terminals of the second normally open contact KM12; The first fuse FU1 connected in series with the first input terminal L1 is also connected in series with the second fuse FU2, and the series connection is connected to the first thermal relay FR1 and one end of the AC contactor KM1 in sequence; The first fuse FU1 connected in series with the second input terminal L2 is also connected in series with the second fuse FU2. After the series connection, the second fuse FU2 is connected to the other end of the AC contactor KM1. The first fuse FU1 connected in series with the third input terminal L3 is connected to a first connection end of the second normally open contact KM12.

6. The energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump as claimed in claim 5, characterized in that: The second normally open contact KM12 is connected to one end of the second thermal relay FR2, and the other end of the second thermal relay FR2 is connected to the permanent magnet synchronous motor through a cable.

7. The energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump as claimed in claim 5, characterized in that: A start button SB1 and a stop button SB2 are disposed between the first thermal relay FR1 and the AC contactor KM1; and the start button SB1 and the stop button SB2 are disposed on the door of the control cabinet.

8. The energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump as claimed in claim 7, characterized in that: The start button SB1 and the stop button SB2 are connected in series, and a first normally open contact KM11 is connected in parallel to both ends of the start button SB1.

9. An energy-consuming braking anti-reversal method based on the energy-consuming braking anti-reversal device for a permanent magnet motor direct-driven electric submersible centrifugal pump as claimed in any one of claims 1 to 8, characterized in that: include: When the permanent magnet synchronous motor is started, the circuit breaker QS is pressed, and then the start button SB1 is pressed. The three-phase AC passes through the first fuse FU1 and the second fuse FU2, so that the AC contactor KM1 is energized. At this time, the first normally open contact KM11 and the second normally open contact KM12 are closed, and the normally closed contact KM13 is disconnected. The three-phase AC passes through the circuit breaker QS, the first fuse FU1, the second normally open contact KM12, the first thermal relay FR1, and the second thermal relay FR2 into the permanent magnet synchronous motor, and the motor starts to run normally. At this time, the energy-consuming braking circuit does not consume the electric energy of the main circuit; When the power grid is suddenly powered off or the stop button SB2 is pressed, the AC contactor KM1 loses power, the first normally open contact KM11 and the second normally open contact KM12 are disconnected, the normally closed contact KM13 is closed, the permanent magnet synchronous motor is powered off, and the permanent magnet synchronous motor reverses to generate three-phase AC power. The three-phase AC power flows into the rectifier circuit U1 through the normally closed contact KM13 and the first energy consumption resistor R1, forms DC power after rectification, and enters the energy consumption circuit U2 to consume the electric energy generated by the reversal of the permanent magnet synchronous motor PMSM.

10. The anti-reverse method of dynamic braking according to claim 9, characterized in that: The permanent magnet synchronous motor generates three-phase AC power when it reverses. The energy consumption circuit U2 consumes the electric energy generated by the permanent magnet synchronous motor PMSM when it reverses, including: The supercapacitor C is responsible for absorbing the excess electrical energy in the circuit, and the first energy consumption resistor R1 prevents excessive current from damaging the circuit and consumes part of the electrical energy; When the supercapacitor C reaches a full charge state, the voltage across it increases, the insulated gate bipolar transistor VT is turned on, and the second energy dissipation resistor R2 is connected to the circuit to accelerate the consumption of electric energy and enhance the braking effect of the permanent magnet synchronous motor PMSM until the motor stops reversing.

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