A permanent magnet synchronous motor for submersible oil pump and a method for reducing magnetic leakage

Abstract

The present invention relates to a permanent magnet synchronous motor for a submersible oil pump and a method for reducing magnetic leakage, belonging to the technical field of synchronous motors for rodless lifting mechanical oil production. The technical solution is as follows: The rotor sheet (6) is polygonal, and a number of sector intervals equal to the number of sides of the polygon are formed on the rotor sheet (6). The number of sides of the polygon is the same as the number of permanent magnets (7) on the rotor sheet (6); the distance between two adjacent permanent magnets (7) on the rotor sheet (6) is relatively large, and the interval formed between this distance is called the reinforcing rib (11), and the distance between the permanent magnet (7) on the rotor sheet (6) and the outer edge of the rotor sheet is relatively small, and the interval formed by this distance is called the weakening rib (12). The beneficial effects of the present invention are as follows: It improves the performance and service life of the submersible motor, reduces the magnetic leakage phenomenon, enhances the magnetic field intensity, thereby increasing the back electromotive force of the motor and increasing the power density of the motor.

Description

Technical Field

[0001] The present invention relates to a permanent magnet synchronous motor for a submersible oil pump and a method for reducing magnetic leakage, belonging to the technical field of rodless lifting mechanical oil production synchronous motors. Background Art

[0002] At present, in the mechanical oil production mode, the rod pumping system dominates, followed by the electrical submersible centrifugal pump oil production system and the submersible screw pump system. However, with the continuous development of oil fields, the number of deep wells and directional wells is gradually increasing, and the number of high-sand, high-wax, and high-gas crude oil wells is increasing, which brings many problems to rod pumping, such as serious rod-tube eccentric wear and difficult downward movement of the sucker rod. Rodless lifting mechanical oil production can effectively solve the above problems. Rodless lifting mechanical oil production is a pumping device that does not rely on sucker rods to transmit power and realizes oil production through a rodless pump. The motor used in the rodless pump is a submersible induction motor, which directly drives an electrical submersible centrifugal pump or drives a screw pump by adding a planetary gear reducer. The problems of the submersible induction motor are: low work efficiency and power factor, and the system efficiency is further reduced after adding a reducer, and the number of failure points increases. The use of a permanent magnet synchronous motor can effectively solve the above problems. However, the rotor sheet (the entire rotor cross-section) of the permanent magnet synchronous motor in the prior art is circular. Although the circular rotor is easy to process, the magnetic leakage phenomenon is relatively serious, which affects the magnetic field strength and the back electromotive force of the motor, resulting in a decrease in the motor power density. Summary of the Invention

[0003] The purpose of the present invention is to provide a permanent magnet synchronous motor for a submersible oil pump and a method for reducing magnetic leakage, improve the performance and service life of the submersible motor, reduce the magnetic leakage phenomenon, enhance the magnetic field strength, thereby increasing the back electromotive force of the motor and increasing the motor power density, and solve the problems existing in the background art.

[0004] The technical solution of the present invention is as follows:

[0005] A permanent magnet synchronous motor for a submersible oil pump, comprising a stator housing, electromagnetic wires, stator laminations, rotor laminations, permanent magnets and a rotor shaft; the stator laminations are press-fitted into the stator housing, and the electromagnetic wires are passed through to form the stator; the rotor laminations are provided with magnet holes, and the magnet holes are filled with permanent magnets to form the rotor. The rotor laminations filled with permanent magnets are sleeved on the rotor shaft, and the rotor and the rotor shaft are inserted into the stator. After being powered on, the magnetic field generated by the electromagnetic wires and the magnetic field generated by the permanent magnets interact with each other to drive the rotor shaft to rotate and output power; the cross-section of the rotor is polygonal, the rotor laminations are polygonal, and a number of fan-shaped intervals equal to the number of sides of the polygon are formed on the rotor laminations. The magnet holes are arranged at the centers of the fan-shaped intervals, one magnet hole is arranged on each fan-shaped interval, and one permanent magnet is filled in each magnet hole. The number of sides of the polygon is the same as the number of permanent magnets on the rotor laminations; the distance between two adjacent permanent magnets on the rotor laminations is relatively large, and the interval formed by this distance is called a reinforcing rib. The distance between the permanent magnets on the rotor laminations and the outer edge of the rotor laminations is relatively small, and the interval formed by this distance is called a weakening rib.

[0006] The width of the weakening rib is much smaller than that of the reinforcing rib. The width of the weakening rib is 1 mm - 3 mm, and the minimum width of the reinforcing rib is 2 mm - 5 mm.

[0007] The outside of the rotor is wrapped with epoxy resin and Tianwei fiberglass tape in a semi-overlapping and cross-wound manner to form a filling layer with a thickness of 2 mm - 3 mm, and then the overall outer circle is machined to a circular shape by a lathe.

[0008] The number of magnet holes on the rotor laminations is 4 - 20, which is determined according to the different requirements of low speed and high speed of the motor.

[0009] The stator leads out sensor signal wires, and the sensor signal wires are connected to sensors to measure parameters such as the voltage, current and temperature of the motor.

[0010] The rotor laminations filled with permanent magnets are in multiple sections and are sleeved on the rotor shaft one by one. A centering bearing is provided between the rotor laminations. The rotor shaft with the rotor is inserted into the stator, and a motor head and a motor tail seat are respectively installed at both ends.

[0011] A method for reducing magnetic leakage of a permanent magnet synchronous motor for a submersible oil pump. The stator laminations are pressed into the stator housing, and electromagnetic wires are passed through to form the stator. The rotor laminations are provided with magnet holes, and the magnet holes are filled with magnets to form the rotor. The rotor laminations filled with magnets are put on the rotor shaft, and the rotor and the rotor shaft are inserted into the stator. After power is applied, the magnetic field generated by the electromagnetic wires and the magnetic field generated by the magnets interact to drive the rotation of the rotor shaft to output power. The cross-section of the rotor is polygonal, the rotor laminations are polygonal, and the number of sides of the polygon is the same as the number of magnets on the rotor laminations. The distance between two adjacent magnets on the rotor laminations is relatively large, which is called the strengthening rib, and the distance between the magnet on the rotor lamination and the outer edge of the rotor lamination is relatively small, which is called the weakening rib. The magnetic circuit of the rotor: from the N pole of the common end between two magnets to the S pole of the common end between two magnets, the magnetic circuit passes through the magnetic field generated by the magnets, and forms a magnetic circuit with the stator along the strengthening rib, avoiding forming a magnetic circuit through the weakening rib to weaken the magnetic field strength.

[0012] The width of the weakening rib is as small as possible. Magnetic pulling force will be generated at the strengthening rib, and the strengthening rib can also prevent the deformation of the rotor laminations.

[0013] The outer shape of the rotor is polygonal. To reduce friction, the outer surface of the rotor is wrapped with epoxy resin and Tianwei fiberglass tape in a semi-overlapping and cross-winding manner to form a filling layer with a thickness of 2 mm - 3 mm, and then the overall outer circle is machined to a circular shape by a lathe.

[0014] The beneficial effects of the present invention are: improving the performance and service life of the submersible oil motor, reducing the magnetic leakage phenomenon, enhancing the magnetic field strength, thereby increasing the back electromotive force of the motor and increasing the power density of the motor. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of an embodiment of the present invention;

[0016] Figure 2 It is a schematic structural diagram of a rotor lamination of an embodiment of the present invention;

[0017] In the figure: motor head 1, stator housing 2, sensor signal wire 3, electromagnetic wire 4, stator lamination 5, rotor lamination 6, magnet 7, centering bearing 8, rotor shaft 9, motor tail seat 10, strengthening rib 11, weakening rib 12. Detailed Embodiments

[0018] The following further illustrates the present invention through examples in conjunction with the accompanying drawings.

[0019] A permanent magnet synchronous motor for a submersible oil pump, comprising a stator housing 2, electromagnetic wires 4, stator laminations 5, rotor laminations 6, permanent magnets 7 and a rotor shaft 9; the stator laminations 5 are press-fitted into the stator housing 2, and the electromagnetic wires 4 are inserted through to form the stator; the rotor laminations 6 are provided with magnet holes, and the magnet holes are filled with permanent magnets 7 to form the rotor. The rotor laminations filled with permanent magnets are put on the rotor shaft 9, and the rotor and the rotor shaft 9 are inserted into the stator. After being powered on, the magnetic field generated by the electromagnetic wires and the magnetic field generated by the permanent magnets interact with each other to drive the rotation of the rotor shaft 9 to output power; the cross-section of the rotor is polygonal, the rotor laminations 6 are polygonal, and a number of fan-shaped intervals equal to the number of sides of the polygon are formed on the rotor laminations 6. The magnet holes are arranged at the centers of the fan-shaped intervals, one magnet hole is arranged on each fan-shaped interval, and one permanent magnet 7 is filled in each magnet hole. The number of sides of the polygon is the same as the number of permanent magnets 7 on the rotor laminations 6; the distance between two adjacent permanent magnets 7 on the rotor laminations 6 is relatively large, and the interval formed between this distance is called a reinforcing rib 11. The distance between the permanent magnets 7 on the rotor laminations 6 and the outer edge of the rotor laminations is relatively small, and the interval formed by this distance is called a weakening rib 12.

[0020] The width of the weakening rib 12 is much smaller than the width of the reinforcing rib. The width of the weakening rib 12 is 1 mm - 3 mm, and the minimum width of the reinforcing rib 11 is 2 mm - 5 mm.

[0021] The outside of the rotor is wrapped with epoxy resin and Tianwei fiberglass tape in a semi-overlapping and cross-winding manner to form a filling layer with a thickness of 2 mm - 3 mm, and then the overall outer circle is machined to a circular shape by a lathe.

[0022] The number of magnet holes on the rotor laminations is 4 - 20, which is determined according to the different requirements of the motor for low speed and high speed.

[0023] The stator leads out sensor signal wires 3, and the sensor signal wires are connected to sensors to measure parameters such as the voltage, current and temperature of the motor.

[0024] The rotor laminations filled with permanent magnets are in multiple sections, and are put on the rotor shaft 9 one by one. A centering bearing 8 is provided between the rotor laminations. The rotor shaft with the rotor is inserted into the stator, and the motor head 1 and the motor tail seat 10 are respectively installed at both ends.

[0025] A method for reducing magnetic leakage of a permanent magnet synchronous motor for a submersible oil pump. The stator laminations 5 are pressed into the stator housing 2, and electromagnetic wires 4 are inserted to form the stator. The rotor laminations 6 are provided with magnet holes, and magnets 7 are filled in the magnet holes to form the rotor. The rotor laminations filled with magnets are put on the rotor shaft 9, and the rotor and the rotor shaft 9 are inserted into the stator. After power-on, the magnetic field generated by the electromagnetic wires and the magnetic field generated by the magnets interact to drive the rotation of the rotor shaft 9 to output power. The cross-section of the rotor is polygonal, the rotor laminations 6 are polygonal, and the number of sides of the polygon is the same as the number of magnets 7 on the rotor laminations 6. The distance between two adjacent magnets 7 on the rotor laminations 6 is relatively large, which is called the reinforcing rib 11, and the distance between the magnet 7 on the rotor laminations 6 and the outer edge of the rotor laminations is relatively small, which is called the weakening rib 12. The magnetic circuit of the rotor: from the N pole at the common end between two magnets to the S pole at the common end between two magnets, the magnetic circuit passes through the magnetic field generated by the magnets, and forms a magnetic circuit with the stator along the reinforcing rib to avoid weakening the magnetic field intensity by generating a magnetic circuit through the weakening rib.

[0026] The width of the weakening rib 11 is as small as possible. Magnetic pulling force will be generated at the reinforcing rib 12, and the reinforcing rib can also prevent the deformation of the rotor laminations.

[0027] The outer shape of the rotor is polygonal. To reduce friction, the outside of the rotor is wrapped with epoxy resin and Tianwei fiberglass tape in a semi-overlapping cross-winding manner to form a filling layer with a thickness of 2 mm - 3 mm, and then the overall outer circle is machined to a circular shape by a lathe.

[0028] In the embodiment, refer to the attached Figure 1 、 2 。

[0029] The cross-section of the rotor is a tetradecagon, the rotor laminations 6 are tetradecagons, fourteen fan-shaped intervals are formed on the rotor laminations 6, the magnet holes are arranged at the centers of the fan-shaped intervals, one magnet hole is arranged on each fan-shaped interval, and one magnet 7 is filled in the magnet hole. The number of magnets 7 on the rotor laminations 6 is fourteen; the distance between two adjacent magnets 7 on the rotor laminations 6 is relatively large, and the interval formed between this distance is called the reinforcing rib 11, and the distance between the magnet 7 on the rotor laminations 6 and the outer edge of the rotor laminations is relatively small, and the interval formed by this distance is called the weakening rib 12.

[0030] The width of the weakening rib 12 is much smaller than the width of the reinforcing rib, the width of the weakening rib 12 is 1 mm, and the minimum width of the reinforcing rib 11 is 2 mm.

[0031] The outside of the rotor is wrapped with epoxy resin and Tianwei fiberglass tape in a semi-overlapping cross-winding manner to form a filling layer with a thickness of 2 mm, and then the overall outer circle is machined to a circular shape by a lathe.

[0032] The stator leads out the sensor signal line 3, and the sensor signal line is connected to the sensor to measure parameters such as the motor voltage, current and motor temperature.

[0033] The rotor sheets filled with magnets, with multiple sections, are sleeved onto the rotor shaft 9 one by one. A centering bearing 8 is provided between the rotor sheets. The rotor shaft with the rotor is inserted into the stator, and the motor head 1 and the motor tail seat 10 are respectively installed at both ends.

[0034] Magnetic circuit of the rotor: flowing from the N pole at the common end between two magnets to the S pole at the common end between two magnets, the magnetic circuit passes through the magnetic field generated by the magnets, forms a magnetic circuit along the reinforcing ribs and the stator, and avoids weakening the magnetic field intensity by generating a magnetic circuit through the weakening ribs.

[0035] In the embodiment, the outer circle of the rotor sheet is a tetradecagon, and the inner circle of the rotor sheet is a common circle.

Claims

1. A permanent magnet synchronous motor for a submersible oil pump, characterized in that: It includes a stator housing (2), electromagnetic wires (4), stator laminations (5), rotor laminations (6), permanent magnets (7) and a rotor shaft (9); the stator laminations (5) are press-fitted into the stator housing (2), and the electromagnetic wires (4) are inserted through them to form a stator; the rotor laminations (6) are provided with magnet holes, and the magnet holes are filled with permanent magnets (7) to form a rotor. The rotor laminations (6) filled with permanent magnets are put on the rotor shaft (9), and the rotor and the rotor shaft (9) are inserted into the stator. After being powered on, the magnetic field generated by the electromagnetic wires and the magnetic field generated by the permanent magnets interact with each other to drive the rotation of the rotor shaft (9) to output power; the cross-section of the rotor is polygonal, the rotor laminations (6) are polygonal, and the number of fan-shaped intervals equal to the number of sides of the polygon is formed on the rotor laminations (6). The magnet holes are arranged at the centers of the fan-shaped intervals, one magnet hole is arranged on each fan-shaped interval, and one permanent magnet (7) is filled in each magnet hole. The number of sides of the polygon is the same as the number of permanent magnets (7) on the rotor laminations (6); the distance between two adjacent permanent magnets (7) on the rotor laminations (6) is relatively large, and the interval formed by this distance is called a reinforcing rib (11). The distance between the permanent magnets (7) on the rotor laminations (6) and the outer edge of the rotor laminations is relatively small, and the interval formed by this distance is called a weakening rib (12); the width of the weakening rib (12) is much smaller than the width of the reinforcing rib. The width of the weakening rib (12) is 1 mm - 3 mm, and the minimum width of the reinforcing rib (11) is 2 mm - 5 mm; the outside of the rotor is wound semi-overlappingly and crosswise with epoxy resin and fiberglass tape to form a filling layer.

2. The permanent magnet synchronous motor for submersible oil pump according to claim 1, characterized in that: The number of magnet holes on the rotor laminations (6) is 4 - 20.

3. A permanent magnet synchronous motor for submersible oil pump according to claim 1, characterized in that: The stator leads out a sensor signal wire (3), and the sensor signal wire (3) is connected to a sensor to measure motor voltage, current and motor temperature parameters.

4. A permanent magnet synchronous motor for submersible oil pump according to claim 1 or 3, characterized in that: The rotor laminations (6) filled with permanent magnets are in multiple sections, and are put on the rotor shaft (9) one by one. A centering bearing (8) is provided between the rotor laminations. The rotor shaft with the rotor is inserted into the stator, and a motor head (1) and a motor tailstock (10) are respectively installed at both ends.

5. A method for reducing magnetic leakage of a permanent magnet synchronous motor for submersible oil pump, characterized in that: The stator laminations (5) are press-fitted into the stator housing (2), and the electromagnetic wire (4) is passed through to form the stator; the rotor laminations (6) are provided with magnet holes, and the magnet holes are filled with magnets (7) to form the rotor. The rotor laminations filled with magnets are put on the rotor shaft (9), and the rotor and the rotor shaft (9) are inserted into the stator. After being energized, the magnetic field generated by the electromagnetic wire and the magnetic field generated by the magnets interact with each other to drive the rotation of the rotor shaft (9) to output power; the cross-section of the rotor is polygonal, the rotor laminations (6) are polygonal, and the number of sides of the polygon is the same as the number of magnets (7) on the rotor laminations (6); the distance between two adjacent magnets (7) on the rotor laminations (6) is relatively large, which is called the reinforcing rib (11), and the distance between the magnet (7) on the rotor laminations (6) and the outer edge of the rotor laminations is relatively small, which is called the weakening rib (12); the magnetic circuit of the rotor: from the N pole at the common end between two magnets to the S pole at the common end between two magnets, the magnetic circuit passes through the magnetic field generated by the magnets, and forms a magnetic circuit with the stator along the reinforcing rib to avoid weakening the magnetic field intensity by generating a magnetic circuit through the weakening rib; the outside of the rotor is wrapped with epoxy resin and fiberglass tape in a semi-overlapping and cross-winding manner to form a filling layer with a thickness of 2 mm - 3 mm, and then the overall outer circle is machined to a circular shape by a lathe.

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