Air-gap magnetic field adjustable wide-area high-efficiency drag motor

Abstract

The application discloses a wide-area high-efficiency dragging motor with adjustable air-gap magnetic field, which comprises a rotor iron core and a stator iron core. A plurality of groups of magnetic isolation grooves are formed on the rotor iron core according to the structure of a synchronous reluctance motor. The groups of magnetic isolation grooves are arranged in axial symmetry with the rotating shaft of the rotor iron core. Each group of magnetic isolation grooves is a single magnetic isolation groove structure with multiple layers. A rotor direct-current excitation winding is arranged on the magnetic isolation grooves. The application can be designed for brushless excitation, directly equipped with an exciter, and realize brushless excitation through a rectifier circuit. Alternatively, a harmonic magnetic field induction winding is arranged in the magnetic isolation groove, and the rotor excitation winding is supplied with power after rectification to realize brushless excitation. The pole pair number of the harmonic magnetic field induction winding is half or twice the pole pair number of the rotor excitation winding or the motor.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of drag motors, and particularly relates to a wide-range high-efficiency drag motor with adjustable air-gap magnetic field. BACKGROUND

[0002] Drag motors are widely used in mining fields for hoists, conveyors and other devices, and are the core power source. Mining equipment has the characteristics of large load and wide range of running speed. Motors generally have the ability to have the highest efficiency at the rated operating point, but in the case of light load, overload, ultra-low speed or high speed, the efficiency will decrease, and the output torque cannot meet the requirements. Synchronous reluctance motors have the advantage of wide speed regulation range, and are more suitable for occasions with variable working conditions. However, in the case of a wider working range, the torque may not meet the requirements. Therefore, the requirement that the motor can still work efficiently in a wide working range is a design difficulty of drag motors. SUMMARY

[0003] The application aims to solve the technical problems mentioned in the background.

[0004] Technical scheme: The wide-range high-efficiency drag motor with adjustable air-gap magnetic field comprises a rotor core and a stator core. In the cross-sectional structure, a plurality of groups of magnetic separation grooves are arranged on the rotor core according to the structure of a synchronous reluctance motor, and the plurality of groups of magnetic separation grooves are arranged in a central symmetry with the rotation shaft of the rotor core. Each group of magnetic separation grooves is a single magnetic separation groove structure with multiple layers, and a rotor direct-current excitation winding is arranged on the magnetic separation groove. When the direct-current excitation current flows into the rotor direct-current excitation winding, the generated magnetic field has the same direction as or the opposite direction of the D-axis magnetic field of the rotor core. The size of the D-axis magnetic field is changed by changing the size of the rotor direct-current excitation current, so as to control the size of the torque. When the generated magnetic field has the same direction as the D-axis magnetic field, the motor torque increases. When the generated magnetic field has the opposite direction of the D-axis magnetic field, the motor torque decreases. The D-axis is the direct axis in the motor, and the Q-axis is the cross axis in the motor.

[0005] Further, permanent magnets or ferrite are installed in part of the space of the magnetic separation groove, and the rotor direct-current excitation winding is installed in the remaining space of the magnetic separation groove. The torque density of the motor can be further improved by increasing the permanent magnets or ferrite.

[0006] Further, a rotor additional groove is arranged at the edge of the magnetic separation groove, the rotor additional groove is connected with the adjacent magnetic separation groove, and the rotor direct-current excitation winding is installed on the rotor additional groove. When the distance between the two layers of magnetic separation grooves is large, the space for the rotor direct-current excitation winding can be increased by using this scheme.

[0007] Further, the magnetic isolation grooves of one or more adjacent poles are wound with the rotor DC field winding, which can flexibly configure the winding mode of the rotor DC field winding, facilitating installation and processing.

[0008] Further, the magnetic isolation grooves (4) are 4-6 groups.

[0009] Further, the stator core is provided with stator grooves according to the structure of the synchronous reluctance motor, and the stator armature winding is installed in the stator grooves.

[0010] Further, the stator grooves are further provided with the stator field winding, and the magnetic isolation grooves are further provided with the AC induction winding; after the excitation current is passed through the stator field winding, the AC current is induced on the AC induction winding; the full-wave or half-wave rectifier is used as the rotating rectifier to provide the DC current for the rotor DC field winding, so that the brushless excitation is realized, and the reliability of the application is further increased.

[0011] Further, the brushless excitation is realized by using the excitation machine, the excitation machine adopts the rotating armature type motor structure, is an electric excitation motor, the rotor is coaxially installed with the rotor of the air gap magnetic field adjustable wide-area high-efficiency drag motor, the armature winding of the excitation machine is connected with the output end of the rotating rectifier, the rotating rectifier is full-wave or half-wave rectification, and the current after rectification is passed through the rotor DC field winding.

[0012] Advantages: compared with the prior art, the application has the following remarkable advantages: the motor has more flexible magnetic field modulation capability, can flexibly adjust the difference between the quadrature axis inductance and the direct axis inductance, and expands the motor working range. The application fully utilizes the space of the magnetic isolation bridge, installs the DC field winding, and realizes the brushless excitation without changing the traditional synchronous reluctance motor core structure, and has good popularization. The application can also design the rotor additional slot to accommodate the DC field winding, and increase the flexibility of the scheme. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The core punching structure of the rotor additional slot is taken as an example of a four-pole motor.

[0014] Figure 2 The winding installation mode corresponding to the core of the rotor additional slot.

[0015] Figure 3 The installation mode of the cross-pole type rotor DC field winding.

[0016] Figure 4 The installation mode of the cross-pole type rotor DC field winding without the rotor additional slot.

[0017] Figure 5 The connection mode of each coil of the rotor DC field winding.

[0018] Figure 6 The installation mode of the homopolar rotor DC field winding without rotor additional slot.

[0019] Figure 7 The connection mode of the 8 rotor DC field winding coils.

[0020] Figure 8 The mixed installation mode of the cross-pole and homopolar rotor DC field winding without rotor additional slot.

[0021] Figure 9 The torque superposition principle.

[0022] Figure 10 The air gap magnetic field adjustable wide-area high-efficiency drag motor with added permanent magnet or ferrite.

[0023] Figure 11 The method for realizing brushless air gap magnetic field adjustable wide-area high-efficiency drag motor by using exciter.

[0024] Figure 12 The air gap magnetic field adjustable wide-area high-efficiency drag motor with inductive excitation brushless.

[0025] Wherein, 1. stator core, 2. stator armature winding, 3. stator slot, 4. magnetic separation slot, 5. rotating shaft, 6. rotor DC field winding, 7. rotor additional slot, 8. permanent magnet or ferrite, 9. stator excitation winding, 10. AC induction winding, 11. rotating rectifier, 12. rotor core. 6-1 to 6-8 are the components of the rotor DC field winding 6. DETAILED DESCRIPTION

[0026] The technical solutions of the present application are further described below in combination with the drawings.

[0027] Figure 1 The rotor core punching structure with rotor additional slot. Take a 48-slot 4-pole 3-layer magnetic separation slot 4 motor as an example. The rotor additional slot 7 is opened on the rotor, and the rotor additional slot 7 is connected with the adjacent magnetic separation slot 4. In the specific implementation process, each layer of magnetic separation slot can be selected to increase the corresponding rotor additional slot, or part of the magnetic separation slot can be selected to increase the rotor additional slot.

[0028] Figure 2The winding installation mode corresponding to the rotor core with rotor additional slots 7. The rotor DC field winding 6 is installed in the rotor additional slots 7. A single coil of the rotor DC field winding 6 is wound in the adjacent rotor additional slots 7 in the upper and lower layers, for example, one single coil of the rotor DC field winding 6 is wound in the rotor additional slot 7-1 and the rotor additional slot 7-2. Each element is connected in series to form the rotor DC field winding. The magnetic flux between the adjacent magnetic bridges is adjusted by changing the size and direction of the DC current input to the rotor DC field winding, as shown by the dashed line, thereby affecting the D-axis flux and controlling the size of the D-axis inductance.

[0029] Figure 3 The winding installation mode of the cross-pole rotor DC field winding. The rotor additional slots 7 and the rotor DC field winding 6 can also be placed according to Figure 3 . A single coil of the rotor DC field winding 6 is wound in one rotor additional slot under a certain pole and one rotor additional slot adjacent to the pole. The two rotor additional slots are symmetrical about the symmetry axis shown in Figure 3 .

[0030] Figure 4 The winding installation mode of the cross-pole rotor DC field winding without rotor additional slots 7. When no rotor additional slots are opened, the space of the magnetic slots is directly used to place the rotor DC field winding 6. For example Figure 4 , one coil of the rotor DC field winding is wound in the rotor additional slot 7-1 and the rotor additional slot 7-2. The rotor additional slot 7-1 and the rotor additional slot 7-2 are respectively under adjacent poles and symmetrical about the symmetry axis. The coils of the rotor DC field winding are connected in series. The size of the D-axis flux is adjusted by changing the size and direction of the DC current, thereby affecting the D-axis flux and controlling the size of the D-axis inductance.

[0031] Figure 5 The connection mode of the coils of the rotor DC field winding. As shown, taking a four-pole as an example, the coils 6-1, 6-2, 6-3, and 6-4 of the rotor DC field winding 6 are connected in series. When the DC field current is injected, the constant magnetic field of the NS interlacing can be realized.

[0032] Figure 6 The winding installation mode of the same-pole rotor DC field winding without rotor additional slots in Figure 6 . Another winding installation mode of the rotor field winding coil. The coils of the rotor DC field winding are installed in the adjacent rotor additional slots under the same pole. The directions of the magnetic flux generated by the two coils symmetrical about the symmetry axis are the same when the coils are connected in the circuit.

[0033] Figure 7 The connection mode of the eight coils of the rotor DC field winding. The coils are connected in series.

[0034] Figure 8It is a hybrid installation method of cross-pole and same-pole rotor DC field winding with rotor additional slot 7. The coil of rotor DC field winding can be installed in the magnetic isolation slot under the same pole or in the magnetic isolation slot under the adjacent pole.

[0035] Figure 9 It is torque superposition principle. When the armature current is passed in the armature winding 2, the torque of the motor is superimposed by the magnetic resistance torque and the electric excitation torque.

[0036] Figure 10 It is an air gap magnetic field adjustable wide-area high-efficiency drag motor with added permanent magnet or ferrite 8. The permanent magnet or ferrite is installed in the magnetic isolation slot of the above method to increase the torque density of the motor.

[0037] Figure 11 It is a method of realizing brushless air gap magnetic field adjustable wide-area high-efficiency drag motor by using exciter. The exciter adopts a rotating armature motor structure, which is an electric excitation motor, and its rotor is coaxially installed with the rotor of the air gap magnetic field adjustable wide-area high-efficiency drag motor. The armature winding of the exciter is connected with the output end of the rotating rectifier, and the rotating rectifier is full-wave or half-wave rectification. The current after rectification is passed into the rotor DC field winding.

[0038] Figure 12 It is an air gap magnetic field adjustable wide-area high-efficiency drag motor with induction excitation brushless. In order to solve the problem of brush excitation caused by the installation of rotor DC field winding on the rotor core, the stator excitation winding 9 is installed in the stator slot 3, and the AC induction winding 10 is installed on the magnetic isolation slot. After passing the excitation current in the stator excitation winding 9, the AC current is induced in the AC induction winding 10, and the rotor DC field winding is provided with DC current through the full-wave or half-wave rotating rectifier 11, so as to realize brushless excitation.

Claims

1. A wide-area, high-efficiency traction motor with adjustable air gap magnetic field, comprising a rotor core (12) and a stator core (1), characterized in that: In the cross-sectional structure, the rotor core (12) is provided with a plurality of groups of magnetic isolation slots (4) according to the structure of a synchronous reluctance motor. The plurality of groups of magnetic isolation slots (4) are arranged in a centrally symmetrical manner with respect to the rotating shaft (5) of the rotor core (12). Each group of magnetic isolation slots (4) is a multi-layer single magnetic isolation slot structure. The magnetic isolation slots (4) are provided with a rotor DC excitation winding (6). When a DC excitation current is passed through the rotor DC excitation winding, the direction of the magnetic field generated is the same as or opposite to the direction of the D-axis magnetic field of the rotor core (12). The magnitude of the D-axis magnetic field is changed by changing the magnitude of the rotor DC excitation current, thereby controlling the magnitude of the torque. When the direction of the generated magnetic field is the same as the direction of the D-axis magnetic field, the motor torque increases; when the direction of the generated magnetic field is opposite to the direction of the D-axis magnetic field, the motor torque decreases. A rotor additional slot (7) is provided at the edge of the magnetic isolation slot (4), the rotor additional slot (7) is connected to the adjacent magnetic isolation slot (4), and the rotor DC excitation winding (6) is installed in the rotor additional slot (7); The stator core (1) is provided with stator slots (3) according to the structure of a synchronous reluctance motor, and the stator armature windings (2) are installed in the stator slots (3); A stator excitation winding (9) is also installed in the stator slot (3), and an AC induction winding (10) is also installed on the magnetic isolation slot (4). After an excitation current is passed through the stator excitation winding (9), an AC current is induced on the AC induction winding (10), and a full-wave or half-wave rectified rotating rectifier (11) is used to provide DC power to the rotor DC excitation winding, thereby realizing brushless excitation; An exciter is used to realize brushless excitation. The exciter adopts a rotating armature motor structure and is an electric excitation motor. Its rotor is coaxially installed with the rotor of the air gap magnetic field adjustable wide-area high-efficiency drag motor. The rotating armature winding of the exciter is connected to the output end of the rotating rectifier (11). The rotating rectifier (11) is full-wave or half-wave rectifier. The current after rectification output is passed into the rotor DC excitation winding.

2. The air gap magnetic field adjustable wide-area high-efficiency traction motor according to claim 1, characterized in that: A permanent magnet or ferrite (8) is installed in part of the space of the magnetic isolation slot (4), and a rotor DC excitation winding (6) is installed in the remaining space of the magnetic isolation slot (4).

3. The air gap magnetic field adjustable wide-area high-efficiency traction motor according to claim 1, characterized in that: One or more adjacent two-pole magnetic isolation slots (4) are selected to wind the rotor DC excitation winding (6).

4. The air gap magnetic field adjustable wide-area high-efficiency traction motor according to claim 1, characterized in that: The plurality of groups of magnetic isolation grooves (4) are 4 to 6 groups.

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