A structure of unequal-tooth hybrid excitation motor based on stator partition structure

Abstract

The present invention discloses an unequal-tooth hybrid excitation motor structure based on a stator partition structure, comprising a coaxially arranged outer stator, a rotor, an inner stator and a rotating shaft, wherein the rotor is arranged between the outer stator and the inner stator and coaxially connected to the rotating shaft; the outer stator comprises an outer stator core and an armature winding, wherein the outer stator core is alternately provided with armature teeth and fault-tolerant teeth along the inner circumference, and the armature winding is arranged on the armature teeth and the fault-tolerant teeth; the rotor comprises a plurality of rotor cores and an excitation coil, and the plurality of rotor cores are arranged in a circumferential array, and the excitation coil corresponds to the armature winding one by one; the inner stator comprises an inner stator core and a plurality of groups of first permanent magnet units uniformly distributed at equal intervals along the circumference. The present invention suppresses low-order radial electromagnetic forces through unequal-sized stator tooth structures and star-delta winding connection methods, which can significantly reduce the electromagnetic vibration noise of the motor, and the hybrid excitation structure can improve the flux regulation capability and torque output capability, and adapt to a variety of working conditions.

Description

Technical Field

[0001] The invention relates to motor design technology, and in particular to an unequal-tooth hybrid excitation motor structure based on a stator partition structure. Background Art

[0002] As the actuator of the power system, the motor has been used in more and more occasions. The permanent magnet synchronous motor has the advantages of high power density, high efficiency, simple structure and reliable operation, and has attracted wide attention in the fields of aerospace, electric vehicles and ship propulsion. The continuous improvement of motor power density is one of its important development trends. On the one hand, the motor needs to increase the electromagnetic load, and on the other hand, the motor structure needs to be lightweight, both of which will increase the vibration and noise level of the motor. The vibration of the motor will not only radiate noise outward and reduce the service life of the motor, but also when the motor structure is not designed reasonably, the electromagnetic force in the air gap will resonate with the motor structure, which will produce unpredictable results.

[0003] Preliminary results show that the reduction of electromagnetic vibration noise of permanent magnet motors lies in suppressing low-order radial electromagnetic forces on the one hand, and in designing and optimizing the structural parameters of the motor body on the other hand to avoid resonance between the electromagnetic force of the motor and the structure. The most commonly used method is to modify the motor structural parameters (i.e. modal stiffness and mass) and change the modal frequencies of each order of the motor to achieve the effect of suppressing electromagnetic resonance. However, for speed-controlled permanent magnet synchronous motors, since the frequency of the electromagnetic force changes with the speed, it is difficult to avoid resonance within the entire speed range of the motor. Therefore, suppressing low-order radial electromagnetic forces becomes a more effective way.

[0004] In addition, according to the placement of the permanent magnets, permanent magnet motors can be divided into rotor permanent magnet type and stator permanent magnet type. As a research hotspot in recent years, the stator permanent magnet motor has its permanent magnets and armature windings located on the stator, so the rotor structure is relatively simple, reliable in operation, easy to dissipate heat, and also has the advantages of high power density, high efficiency, good fault tolerance and strong load capacity, so it has good application prospects. However, because the permanent magnet magnetic field is a constant magnetic field, the stator partitioned permanent magnet motor also faces an inherent problem of the permanent magnet motor, that is, the limited magnetic adjustment capability. This limits the constant power operating range of this type of motor. Although vector control can be used to apply a negative direct-axis current component (-I d ) is used to weaken the air gap magnetic field, but due to the limitations of armature current, inverter capacity, etc., the speed regulation range is very limited, and the efficiency and power factor in the weak magnetic speed increase range are low. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide an unequal-tooth hybrid excitation motor structure based on a stator partition structure.

[0006] Technical solution: The present invention provides an unequal-tooth hybrid excitation motor structure based on a stator partition structure, comprising a coaxially arranged outer stator, a rotor, an inner stator and a rotating shaft, wherein the rotor is arranged between the outer stator and the inner stator and coaxially connected to the rotating shaft, a first air gap is arranged between the outer stator and the rotor, and a second air gap is arranged between the inner stator and the rotor;

[0007] The outer stator comprises an outer stator core and an armature winding, wherein the outer stator core is provided with armature teeth and fault-tolerant teeth alternately along the inner circumference, and the armature winding is provided on the armature teeth and the fault-tolerant teeth;

[0008] The rotor includes a plurality of rotor cores and excitation coils, and the plurality of rotor cores are arranged in a circumferential array, corresponding to the armature teeth and the fault-tolerant teeth one by one, and an excitation coil is arranged on each rotor core;

[0009] The inner stator comprises an inner stator core and a plurality of first permanent magnet units which are evenly distributed along the circumference at equal intervals, and the first permanent magnet units correspond to the excitation coils one by one.

[0010] Preferably, the armature winding is connected in a star-delta manner, and each phase winding is composed of a set of star windings and a set of delta windings. The star windings and delta windings are symmetrically distributed in space, and the three-phase windings of the motor are also symmetrically arranged in space.

[0011] Preferably, the armature teeth and the fault-tolerant teeth are of different sizes, forming an unequal tooth structure, and the armature magnetomotive force amplitude of the motor is related to the armature tooth angle α, and the relationship is expressed as:

[0012]

[0013] Among them, F s Represents the armature magnetomotive force amplitude, v s Indicates the harmonic order.

[0014] Preferably, the armature teeth are T-shaped convex teeth, and the fault-tolerant teeth are rectangular convex teeth.

[0015] Preferably, a closed slot is provided in the middle of each rotor core, and the excitation coil is arranged in the closed slot.

[0016] Preferably, a plurality of groups of open slots opening radially outward are evenly distributed at equal intervals along the circumference of the inner stator core, and the first permanent magnet units are arranged in the open slots.

[0017] Preferably, the opening slot is in a straight line shape, and the first permanent magnet unit is a long strip permanent magnet.

[0018] Preferably, the permanent magnet materials are all ferrite materials.

[0019] Preferably, each group of first permanent magnet units is magnetized along the radial direction of the inner stator core, and the magnetization directions of two adjacent groups of first permanent magnet units are opposite.

[0020] Preferably, when the excitation magnetic flux generated by the DC current passed through the excitation coil is in the same direction as the permanent magnetic flux generated by the first permanent magnetic unit, the motor is magnetized; when the excitation magnetic flux generated by the DC current passed through the excitation coil is in the opposite direction to the permanent magnetic flux generated by the first permanent magnetic unit, the motor is magnetized.

[0021] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0022] (1) The present invention adopts a stator partition structure, and the internal space of the motor is fully utilized; different from the traditional hybrid excitation motor, the three-zone structure of the inner and outer stators and the rotor provides more sufficient placement space for the excitation coil, the armature winding, and the permanent magnet, reducing the mutual restrictions on the usage of the three, greatly improving the space utilization of the motor, and making more topological structure combinations possible;

[0023] (2) The present invention utilizes an unequal-tooth stator structure to effectively weaken the low-order harmonics of the armature winding, thereby weakening the amplitude of the radial electromagnetic force generated by the armature winding and the fundamental magnetic flux density; and adopts a star-delta winding connection method to further eliminate the harmonic components of the low-order armature magnetomotive force, effectively reducing the amplitude of the low-order radial electromagnetic force;

[0024] (3) The motor structure provided by the present invention can meet the torque requirements of the motor under high torque conditions and the high efficiency requirements under high-speed conditions. When the motor has a high torque requirement, the permanent magnet flux can be superimposed on the excitation flux by the addition of the excitation current, thereby increasing the flux density and output torque of the motor; in high-speed conditions, the excitation winding inputs opposite currents, at which time the permanent magnet flux and the excitation flux are in opposite directions, thereby enhancing the weak magnetic field speed regulation capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural front view of the unequal-tooth hybrid excitation motor with a stator partition structure proposed by the present invention;

[0026] Figure 2 It is a schematic diagram of the inner and outer stator cores and the rotor core;

[0027] Figure 3 is a schematic diagram of the first permanent magnet unit and the excitation coil;

[0028] Figure 4 This is a schematic diagram of the star-delta winding connection;

[0029] Figure 5 This is the armature winding connection diagram;

[0030] Figure 6It is a magnetic circuit principle diagram of the motor excitation winding in the present invention when no current flows through the motor excitation winding;

[0031] Figure 7 It is a magnetic circuit principle diagram of the motor in the present invention under high torque working condition;

[0032] Figure 8 It is a magnetic circuit principle diagram of the motor in the present invention under high-speed working conditions;

[0033] In the figure: 1 outer stator, 1-1 outer stator core, 1-2 armature winding, 1-3 armature teeth, 1-4 fault-tolerant teeth; 2 rotor, 2-1 rotor core, 2-2 excitation coil, 2-3 closed slot; 3 inner stator, 3-1 inner stator core, 3-2 open slot, 4 rotating shaft, 5 first permanent magnet unit, 5-1 long strip permanent magnet; α armature tooth angle, a permanent magnet flux, b excitation winding, c excitation flux. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the embodiments are not intended to limit the present invention. All similar structures and similar variations of the present invention should be included in the protection scope of the present invention. The commas in the present invention all represent the relationship of and.

[0035] like Figure 1 and Figure 2 As shown, an unequal-tooth hybrid excitation motor structure based on a stator partition structure comprises: a coaxially arranged outer stator 1, a rotor 2, an inner stator 3 and a rotating shaft 4, the rotor 2 is arranged between the outer stator 1 and the inner stator 3, and is coaxially connected to the rotating shaft 4, the inner stator 3 is sleeved on the rotating shaft 4, a first air gap is arranged between the outer stator 1 and the rotor 2, and a second air gap is arranged between the inner stator 3 and the rotor 2; the outer stator 1 is composed of an outer stator core 1-1 and an armature winding 1-2, the outer stator core 1-1 is alternately provided with armature teeth 1-3 and fault-tolerant teeth 1-4 along the inner circumference, and the armature winding 1-2 is arranged on the armature Teeth 1-3 and fault-tolerant teeth 1-4; the rotor 2 is composed of 12 segmented rotor cores 2-1 and excitation coils 2-2, and the rotor cores 2-1 are arranged in a circumferential array, corresponding one to one with the armature teeth 1-3 and the fault-tolerant teeth 1-4, and an excitation coil 2-2 is arranged on each rotor core 2-1, and the rotor is located between the outer stator core 1-1 and the inner stator core 3-1; the inner stator 3 is composed of an inner stator core 3-1 and 12 groups of first permanent magnet units 5 uniformly distributed at equal intervals along the circumference, and the first permanent magnet unit 5 is "1" type (or straight line type), which corresponds one to one with the excitation coil 2-2.

[0036] See also Figure 1 and Figure 2In this embodiment, the outer stator core 1-1 includes 6 armature teeth and 6 fault-tolerant teeth, the armature teeth and the fault-tolerant teeth are arranged alternately, the armature teeth 1-3 and the fault-tolerant teeth 1-4 are different in size, forming an unequal tooth structure, and the armature magnetomotive force amplitude of the motor is related to the armature tooth angle α, and the relationship can be expressed as:

[0037]

[0038] Among them, F s Represents the armature magnetomotive force amplitude, v s Indicates the harmonic order.

[0039] See also Figure 1 , Figure 2 and Figure 3 In this embodiment, 12 groups of open slots 3-2 with openings facing radially outward in a "1" shape are evenly distributed along the circumference of the inner stator core 3-1. A square closed slot 2-3 is arranged in the middle of each rotor core 2-1. Each group of first permanent magnet units 5 is composed of a long strip permanent magnet 5-1 arranged in a "1" shape, and is arranged in the "1" shape open slots 3-2 evenly distributed along the circumference. Each long strip permanent magnet 5-1 is magnetized along the length direction of the permanent magnet (that is, magnetized along the radial direction of the inner stator core), and the magnetization directions of two adjacent groups of long strip permanent magnets 5-1 are opposite. The permanent magnet material is ferrite material. The number of the first permanent magnet units 5 is consistent with the number of the armature windings 1-2.

[0040] See also Figure 1 , Figure 2 and Figure 3 The excitation coil 2-2 is arranged in the square closed slot 2-3, and the number of the excitation coil 2-2 is the same as the number of the armature winding 1-2; when the excitation magnetic circuit generated by the DC current is in the same direction as the magnetic circuit generated by the first permanent magnet unit 5, the motor is magnetized; when the excitation magnetic circuit generated by the DC current is in the opposite direction to the magnetic circuit generated by the first type of permanent magnet unit 5, the motor is weakened.

[0041] See also Figure 4 and Figure 5 The armature winding 1-2 adopts a star-delta connection method, and each phase winding is composed of a set of star windings and a set of delta windings. The star windings and the delta windings are symmetrically distributed in space, so the three-phase windings of the motor are also symmetrically arranged in space.

[0042] See also Figure 6 In the motor structure of the present invention, when there is no current input to the excitation winding, there is only a permanent magnet magnetic circuit in the magnetic circuit.

[0043] like Figure 7As shown, when the motor of the present invention has a large torque demand, the DC current passed through the excitation winding b generates an excitation flux c which has the same direction as the permanent magnet flux a generated by the first permanent magnet unit. The permanent magnet flux and the excitation flux are superimposed, and have the characteristic of large air gap magnetic density, thereby improving the motor output torque and meeting the large torque working conditions such as electric vehicles climbing.

[0044] like Figure 8 As shown, when the motor of the present invention is in high-speed operation, the direct current flowing through the excitation winding b generates an excitation flux c which is in the opposite direction to the permanent magnetic flux a generated by the first permanent magnetic unit, thereby producing a weak magnetic effect.

Claims

1. An unequal-tooth hybrid excitation motor structure based on a stator partition structure, characterized in that: The invention comprises an outer stator (1), a rotor (2), an inner stator (3) and a rotating shaft (4) which are coaxially arranged, wherein the rotor (2) is arranged between the outer stator (1) and the inner stator (3) and is coaxially connected to the rotating shaft (4), a first air gap is arranged between the outer stator (1) and the rotor (2), and a second air gap is arranged between the inner stator (3) and the rotor (2); The outer stator (1) comprises an outer stator iron core (1-1) and an armature winding (1-2); the outer stator iron core (1-1) is alternately provided with armature teeth (1-3) and fault-tolerant teeth (1-4) along the inner circumference; and the armature winding (1-2) is arranged on the armature teeth (1-3) and the fault-tolerant teeth (1-4); The rotor (2) comprises a plurality of rotor cores (2-1) and excitation coils (2-2), and the plurality of rotor cores (2-1) are arranged in a circumferential array, corresponding one-to-one to the armature teeth (1-3) and the fault-tolerant teeth (1-4), and an excitation coil (2-2) is provided on each rotor core (2-1); The inner stator (3) comprises an inner stator iron core (3-1) and a plurality of groups of first permanent magnet units (5) uniformly distributed at equal intervals along the circumference, and the first permanent magnet units (5) correspond one to one to the excitation coils (2-2).

2. According to claim 1, an unequal-tooth hybrid excitation motor structure based on a stator partition structure is characterized in that: The armature winding (1-2) adopts a star-delta connection method, and each phase winding is composed of a set of star windings and a set of delta windings. The star windings and the delta windings are symmetrically distributed in space, and the three-phase windings of the motor are also symmetrically arranged in space.

3. The unequal-tooth hybrid excitation motor structure based on the stator partition structure according to claim 1 is characterized in that: The armature teeth (1-3) and the fault-tolerant teeth (1-4) are different in size, forming an unequal tooth structure, and the armature magnetomotive force amplitude of the motor is related to the armature tooth angle α, and the relationship is expressed as: Among them, F s Represents the armature magnetomotive force amplitude, v s Indicates the harmonic order.

4. The unequal-tooth hybrid excitation motor structure based on the stator partition structure according to claim 1 is characterized in that: The armature teeth (1-3) are T-shaped convex teeth, and the fault-tolerant teeth (1-4) are rectangular convex teeth.

5. The unequal-tooth hybrid excitation motor structure based on the stator partition structure according to claim 1 is characterized in that: A closed slot (2-3) is arranged in the middle of each rotor iron core (2-1), and the excitation coil (2-2) is arranged in the closed slot (2-3).

6. The unequal-tooth hybrid excitation motor structure based on the stator partition structure according to claim 1 is characterized in that: A plurality of groups of open slots (3-2) with openings facing radially outward are evenly distributed at equal intervals along the circumference of the inner stator core (3-1), and the first permanent magnet units (5) are arranged in the open slots (3-2).

7. The unequal-tooth hybrid excitation motor structure based on the stator partition structure according to claim 6 is characterized in that: The opening slot (3-2) is in the shape of a straight line, and the first permanent magnet unit (5) is a straight-line long strip permanent magnet (5-1).

8. The unequal-tooth hybrid excitation motor structure based on the stator partition structure according to claim 7 is characterized in that: Permanent magnet materials are all ferrite materials.

9. The unequal-tooth hybrid excitation motor structure based on the stator partition structure according to claim 1 is characterized in that: Each group of first permanent magnet units (5) is magnetized radially along the inner stator core (3-1), and the magnetization directions of two adjacent groups of first permanent magnet units (5) are opposite.

10. The unequal-tooth hybrid excitation motor structure based on the stator partition structure according to claim 1 is characterized in that: When the excitation magnetic flux generated by the direct current passed through the excitation coil (2-2) has the same direction as the permanent magnetic flux generated by the first permanent magnetic unit (5), the motor is magnetized; when the excitation magnetic flux generated by the direct current passed through the excitation coil (2-2) has the opposite direction to the permanent magnetic flux generated by the first permanent magnetic unit (5), the motor is magnetized.

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