Submersible mixed magnetic synchronous reluctance motor

Abstract

The invention relates to the technical field of motors, and discloses a submersible mixed magnetic synchronous reluctance motor which comprises a stator core, a plurality of stator grooves are formed in the stator core, a rotor core is arranged in the stator core in a sleeved mode, a plurality of rotor grooves are formed in the rotor core, and a plurality of rotor grooves are formed in the rotor core in a sleeved mode. The stator slots are uniformly and annularly distributed in the stator core and form stator teeth, the rotor slots comprise a plurality of triangular slots and a plurality of arc-shaped slots, the linear slots are uniformly and annularly formed in the periphery of the rotor core, and the arc-shaped slots are uniformly and annularly formed in the middle of the rotor core. Magnetism is gathered through a unique triangular groove rotor structure, the utilization rate of permanent magnet steel and the efficiency of the motor are improved, the speed regulation range is widened, and high-speed operation safety is guaranteed through a limiting structure. The fractional slot concentrated winding improves the slot fullness rate, reduces the copper wire consumption and energy consumption heating, improves the performance and effectively controls the cost.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a submersible oil-mixed synchronous reluctance motor. Background Art

[0002] The current submersible hybrid synchronous reluctance motor is a submersible motor that combines permanent magnet and reluctance technologies. Its stator generally adopts the stator structure of a traditional three-phase AC motor, while the rotor features a multi-layered, arc-shaped structure with unequal magnetic barriers and embedded tile-type ferrite permanent magnets. This design increases the reluctance torque ratio, enhancing torque output and high-temperature stability while reducing costs.

[0003] Among oil production methods, submersible pump systems have become essential equipment for oilfield production due to their unique advantages. These include the absence of sucker rods, which eliminates rod-tubing wear, and the prevention of sand sticking, scaling, and gas locks during crude oil extraction. As the power source for these systems, submersible motors play a crucial role in the overall operation of the unit.

[0004] The rotors of existing submersible hybrid synchronous reluctance motors lack V-grooves, resulting in poor magnetic field concentration, low permanent magnet utilization, limited motor efficiency, and a narrow speed regulation range. Magnetic assembly is complex and unstable, making them prone to falling off during high-speed operation. Furthermore, the slot fill rate is low, copper wire usage is high, energy consumption is high, and heat generation is severe. Furthermore, control strategies struggle to accurately adapt to complex well conditions, especially at low flow rates, hindering effective regulation and impacting the overall efficiency of the oil production system. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a submersible oil-hybrid synchronous reluctance motor, which solves the problems of low permanent magnet steel utilization, limited motor efficiency, narrow speed regulation range, low slot fill rate, large amount of copper wire used, high energy consumption and severe heat generation in the existing submersible oil-hybrid synchronous reluctance motor.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a submersible oil hybrid synchronous reluctance motor, including a stator core, a plurality of stator slots are opened inside the stator core, a rotor core is sleeved inside the stator core, a plurality of rotor slots are opened inside the rotor core, and the plurality of stator slots are evenly distributed in an annular shape inside the stator core and form stator teeth.

[0007] Preferably, the rotor slots include a plurality of triangular slots and a plurality of arcuate slots, the plurality of triangular slots are evenly arranged in a ring shape on the outer periphery of the rotor core, and the plurality of arcuate slots are evenly arranged in a ring shape in the middle of the rotor core.

[0008] Preferably, the triangular groove consists of a V-shaped groove and a straight groove.

[0009] Preferably, two ferrites are provided in each of the plurality of straight slots, and two permanent magnets are embedded in each of the plurality of V-shaped slots. The ferrites adopt a segmented structure and can be freely combined into N segments.

[0010] Preferably, the plurality of stator slots (11) are open slots and have a parallel tooth structure.

[0011] Preferably, the stator winding span is 1 slot, and a fractional slot concentrated winding form is adopted.

[0012] Preferably, a magnetic bridge is formed between the plurality of triangular grooves.

[0013] The present invention provides a submersible oil-mixed synchronous reluctance motor. It has the following beneficial effects:

[0014] 1. The present invention uses a unique triangular slot rotor structure to concentrate magnetic field, improve the utilization rate of permanent magnets and motor efficiency, and widen the speed regulation range; the use of segmented ferrite and simple-shaped permanent magnets facilitates assembly and reduces costs, and the limiting structure ensures safe high-speed operation; the fractional slot concentrated winding increases the slot fill rate, reduces copper wire usage and energy consumption and heat generation, achieving performance improvement while effectively controlling costs.

[0015] 2. The present invention uses variable frequency vector control, which can be adjusted in time according to changes in well conditions, eliminating the adverse effects of low flow rate and ensuring maximum production; it has the advantages of low heat generation, fast and ultra-precise control, a large operating range, and permanent magnets synchronize the motor with the magnetic field changes, ensuring stable and efficient operation and improving the overall efficiency of the oil production system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a general cross-sectional view of the motor of the present invention;

[0017] Figure 2 is a schematic cross-sectional view of a stator according to the present invention;

[0018] Figure 3 is a cross-sectional view of the rotor of the present invention;

[0019] Figure 4 This is a schematic diagram of the overall structure of the submersible oil hybrid synchronous reluctance motor of the present invention;

[0020] Figure 5 The torque-speed characteristic diagram of the hybrid synchronous reluctance motor of the present invention;

[0021] Figure 6 This is a power-speed characteristic diagram of the hybrid synchronous reluctance motor of the present invention;

[0022] Figure 7 This is a torque-speed characteristic diagram of a common permanent magnet synchronous motor of the present invention;

[0023] Figure 8 This is a power-speed characteristic diagram of a common permanent magnet synchronous motor of the present invention;

[0024] Figure 9 A cloud diagram of the rated magnetic flux density of the hybrid synchronous reluctance motor of the present invention;

[0025] Figure 10 This is the magnetic field distribution of the hybrid synchronous reluctance motor of the present invention.

[0026] Among them, 1. stator core; 11. stator slots; 12. stator teeth; 2. rotor core; 3. rotor slots; 4. permanent magnets; 5. magnetic bridge; 6. ferrite. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Please see the attached Figure 1 -Attached Figure 4 The present invention provides a submersible oil-assisted hybrid synchronous reluctance motor, comprising a stator core 1 having a plurality of stator slots 11 formed therein. A rotor core 2 is nested within the stator core 1, with a gap between the rotor cores 1 and 2. The motor operates based on a series of electromagnetic principles. First, considering the internal flux linkage relationship, the direct-axis and quadrature-axis flux linkage equations for a permanent magnet-assisted synchronous reluctance motor are:

[0029]

[0030] This equation forms the basis for understanding the flux changes within the motor, where:

[0031] ψd: Direct-axis flux, representing the flux in the direct-axis direction in the motor's dq coordinate system, reflecting the strength and related characteristics of the direct-axis magnetic field.

[0032] ψ q : The quadrature-axis flux is the flux in the quadrature-axis direction in the dq coordinate system of the motor, reflecting the magnetic field conditions in the quadrature-axis direction.

[0033] i d : Direct-axis current, which is the current component in the direct-axis direction in the motor's dq coordinate system, is used to control the motor's magnetic field size and other characteristics.

[0034] i q : The quadrature-axis current is the current component in the quadrature-axis direction in the motor's dq coordinate system, and is mainly used to control the motor's torque.

[0035] L d : Direct-axis inductance refers to the inductance value in the direct-axis direction of the motor, which reflects the ability of the direct-axis current to generate a magnetic field and the characteristics of generating induced electromotive force when the magnetic field changes.

[0036] L q : The quadrature-axis inductance is the inductance value in the quadrature-axis direction of the motor, which affects the relationship between the quadrature-axis current, magnetic field and torque.

[0037] ψ pm : Permanent magnet flux is the flux generated by the permanent magnet of the motor. It is a fixed flux parameter in the permanent magnet synchronous motor and does not change with the current.

[0038] Continuing to delve into the motor structure, the rotor core 2 is provided with a plurality of rotor slots 3, and a plurality of stator slots 11 are evenly distributed in an annular shape inside the stator core 1 and form stator teeth 12. (3) There is a limit structure to prevent the movement of the magnet, and the length is 0.2-0.5mm. The rotor slot 3 includes a plurality of triangular slots and a plurality of arc slots. The plurality of triangular slots are evenly distributed in an annular shape on the outer periphery of the rotor core 2, and the plurality of arc slots are evenly distributed in an annular shape in the middle of the rotor core 2. The triangular slots are composed of V-shaped slots and straight slots. The V-shaped slot rotor structure in the triangular slot is easy to concentrate magnetism, which improves the utilization rate of the permanent magnet steel 4 and the efficiency of the motor. The V-shaped slots and the permanent magnet steel 4 form an evenly distributed magnetic pole unit, which is arranged alternately according to the N pole and the S pole. The material of the permanent magnet steel 4 is 40UH, which is heat-resistant to 180℃. The rotor has 4 groups of 6 layers of permanent magnets to generate permanent magnet torque. The "V"-shaped slots generate magnetic resistance torque, and the speed regulation range is wide. During motor operation, voltage changes have a significant impact on motor performance. The stator voltage equation in a two-phase rotating coordinate system is:

[0039]

[0040] This equation clearly shows the relationship between voltage and motor operating parameters, where:

[0041] u d : Direct axis voltage, which is the component of the stator voltage in the direct axis direction;

[0042] u q : Quadrature axis voltage, which is the component of the stator voltage in the quadrature axis direction;

[0043] i d : Direct axis current, which is the component of the stator current in the direct axis direction, can be used to control the motor magnetic field size and other characteristics;

[0044] i q : The quadrature-axis current is the component of the stator current in the quadrature-axis direction and is mainly used to control the motor torque;

[0045] Rs : Stator resistance, reflecting the stator winding's resistance to current;

[0046] L d : Direct-axis inductance, which reflects the characteristics of the current in the direct-axis direction generating a magnetic field and the change of the magnetic field inducing electromotive force.

[0047] L q : Quadrature-axis inductance, which affects the relationship between quadrature-axis current, magnetic field, and torque;

[0048] ω e : Electrical angular velocity, which indicates how fast the electrical angle of the motor rotates;

[0049] ψ pm : Permanent magnet flux, generated by the permanent magnet of the motor, is a fixed flux parameter and does not change with current.

[0050] Two ferrites 6 are provided in each of the multiple straight slots. The ferrites 6 adopt a segmented structure and can be freely combined into N segments. The segmented ferrite 6, i.e., a segmented iron core, is equivalent to reducing the length of each segment of magnet, facilitating assembly, and reducing the risk of magnets being broken due to excessive length. Two permanent magnets 4 are embedded in each of the multiple V-grooves. The permanent magnets 4 have a simple shape, are suitable for processing, and are easy to install. The amount of permanent magnets used is small, and the cost is low. The V-grooves in the triangular grooves have a limiting structure to prevent the permanent magnets 4 from moving, preventing the built-in structure magnets from falling off at high-speed rotation, and are suitable for weak magnetic speed expansion. Due to the use of a built-in rotor structure, the permanent magnets 4 will not fall off at high speeds, and can be expanded at twice the speed or more. The electromagnetic torque generated by the motor during operation is a key indicator to measure its performance. The electromagnetic torque in the two-phase rotating coordinate system is:

[0051]

[0052] in, is the permanent magnet torque, is the reluctance torque;

[0053] T e : Electromagnetic torque refers to the torque generated when the motor is running and is an important indicator to measure the motor's driving ability;

[0054] p: Motor pole pair number, used to describe the number of magnetic poles in the motor magnetic field, affecting the motor speed and torque characteristics.

[0055] ψ pm : Permanent magnet flux, the flux generated by the motor's permanent magnets, is a fixed parameter and does not change with factors such as current;

[0056] L d : Direct-axis inductance, which reflects the characteristics of the induced electromotive force when the direct-axis current generates a magnetic field and the magnetic field changes;

[0057] L q : Quadrature-axis inductance, which affects the relationship between quadrature-axis current, magnetic field, and torque;

[0058] i d : Direct-axis current, which is the component of the stator current in the direct-axis direction, can be used to control the motor's magnetic field size and other characteristics;

[0059] iq: Quadrature-axis current, the quadrature-axis component of the stator current, is primarily used to control motor torque. This formula indicates that electromagnetic torque is composed of the permanent magnet torque, which is related to the permanent magnet flux linkage and the quadrature-axis current, and the reluctance torque, which is related to the difference between the direct and quadrature-axis inductances and the direct and quadrature-axis currents.

[0060] This formula clarifies the composition of electromagnetic torque and its relationship with various factors.

[0061] Magnetic bridges 5 are formed between multiple triangular grooves. Adjacent magnetic bridges 5 are parallel and spaced 1mm apart, with a length of 0.2-0.5mm. Using variable frequency vector control, the system can make timely adjustments to changing well conditions, optimizing or eliminating the adverse effects of low flow rates, thereby ensuring maximum production. When the motor is actually working, mechanical motion factors must also be considered. Its mechanical motion equation is:

[0062]

[0063] Where, T l is the load torque, T e : electromagnetic torque, ω m is the rotor mechanical angular velocity, J is the moment of inertia, and B is the damping coefficient. This equation fully describes the state of the motor during mechanical operation.

[0064] Therefore, the advantages of low heat generation, high speed and ultra-precise control have expanded the operating range of permanent magnet synchronous reluctance submersible motors. Submersible hybrid synchronous reluctance motors use embedded permanent magnets 4 to enable the motor to operate synchronously with the changing speed of the motor magnetic field.

[0065] Multiple stator slots 11 are open slots and have a parallel tooth structure. The ratio of the inner diameter of the stator core 1 to its outer diameter is less than or equal to 0.67. The spacing between the stator core 1 and the rotor core 2 along the circumference is greater than or equal to 0.7 mm and less than or equal to 1 m. The stator winding span is 1 slot, and a fractional slot concentrated winding form is adopted. The fractional slot concentrated winding improves the slot fill rate, reduces the size of the winding end, reduces the amount of copper wire used, reduces energy consumption, reduces heat generation, and saves costs.

[0066] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A submersible oil-mixed synchronous reluctance motor, comprising a stator core (1), characterized in that: A plurality of stator slots (11) are provided inside the stator core (1), a rotor core (2) is sleeved inside the stator core (1), a plurality of rotor slots (3) are provided inside the rotor core (2), and the plurality of stator slots (11) are evenly distributed in an annular shape inside the stator core (1) and form stator teeth (12).

2. The submersible oil-mixed synchronous reluctance motor according to claim 1, characterized in that: The rotor slots (3) include a plurality of triangular slots and a plurality of arcuate slots, wherein the plurality of triangular slots are evenly arranged in an annular shape on the outer periphery of the rotor core (2), and the plurality of arcuate slots are evenly arranged in an annular shape in the middle of the rotor core (2).

3. The submersible oil-mixed synchronous reluctance motor according to claim 2, characterized in that: The triangular groove consists of a V-shaped groove and a straight groove.

4. The submersible oil-mixed synchronous reluctance motor according to claim 3, characterized in that: Two ferrites (6) are arranged in each of the plurality of straight grooves, and two permanent magnets (4) are arranged in each of the plurality of V-shaped grooves.

5. The submersible oil-mixed synchronous reluctance motor according to claim 1, characterized in that: The plurality of stator slots (11) are open slots and have a parallel tooth structure.

6. The submersible oil-mixed synchronous reluctance motor according to claim 1, characterized in that: The stator winding span is 1 slot, and adopts fractional slot concentrated winding form.

7. The submersible oil-mixed synchronous reluctance motor according to claim 1, characterized in that: A magnetic bridge (5) is formed between the plurality of triangular grooves.

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