A dual-rotor single-stator permanent-magnet disc motor with adjustable air gap and a control method thereof

Abstract

The utility model provides a kind of air gap adjustable double rotor single stator permanent magnet disc type motor and its control method, including shell, motor shaft is provided in shell, a stator and two rotors are installed on motor shaft, two rotors are arranged in the two sides of stator, each rotor includes rotor disc and the rotor disc fixed baffle fixedly connected with rotor disc;Rotor disc fixed baffle rotationally connects with axial tension gear disc;Axial tension gear disc is fixedly provided with axial tension gear, axial tension gear disc is connected with motor shaft by thread;Displacement motor is fixedly installed on rotor disc, displacement motor driving connection has displacement motor gear;The both ends of motor shaft are fixedly provided with conductive copper ring, end cover is fixedly provided with brush, which can be contacted with conductive copper ring, displacement motor is connected with conductive copper ring by wire. The size of double rotor single stator disc type motor air gap is changed using mechanical structure, and then the adjustment of motor air gap magnetic field size is realized, the weak magnetic speed regulation of motor or generator output voltage adjustment is realized.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electric machines, in particular to an air-gap-adjustable double-rotor single-stator permanent-magnet disc-type electric machine and a control method thereof. BACKGROUND

[0002] With the development of modern industry, there is a demand for miniaturization and flattening of electric machines, and disc-type electric machines have been paid attention again. Compared with traditional radial flux electric machines, disc-type electric machines have the characteristics of short axial size and high power density, and are usually applied to special application occasions with limited axial space, such as electric vehicle hub motors, small wind-driven generators, electric bicycles and the like.

[0003] At present, a current-excited synchronous generator is adopted in a turbo-generator, the synchronous generator can adjust the size of an air-gap magnetic field by changing the size of an excitation current, and then adjust the size of an output voltage, so that the output voltage can be conveniently stabilized. Although a permanent-magnet electric machine has high efficiency, the magnetic field of the permanent-magnet electric machine is provided by a permanent magnet, and the size of the air-gap magnetic field of the electric machine is usually adjusted by adjusting the direct-axis current component of a stator winding current, that is, the so-called field-weakening speed regulation, so as to realize high-speed operation of the electric machine. For a permanent-magnet electric machine, this method of adjusting the air-gap magnetic field has been widely used in engineering. However, for a permanent-magnet generator, this method of adjusting the air-gap magnetic field is difficult to realize in engineering, which is the reason why the current turbo-generators all adopt current-excited synchronous generators. The field-weakening speed regulation method needs the stator winding to provide an additional field-weakening current, which increases the copper loss of the stator winding, and needs an additional field-weakening energy provided by a power supply. For a traditional cylindrical radial flux permanent-magnet electric machine, since the air-gap length cannot be adjusted, the method of adjusting the direct-axis current component of the stator winding current is used for adjusting the air-gap magnetic field.

[0004] Unlike the radial flux electric machine, the disc-type electric machine has an axial arrangement of the stator and the rotor, and the air-gap length can be adjusted in the axial direction by taking certain measures, that is, the air-gap magnetic field size can be adjusted by adjusting the air-gap length, and then the field-weakening speed regulation (permanent-magnet disc-type electric machine) or the stable output voltage (permanent-magnet disc-type generator) can be realized.

[0005] In the field of air-gap-adjustable disc-type electric machine patent applications, the prior art 1 (patent No. CN204794586U), the prior art 2 (patent No. CN104993647A), the prior art 3 (patent No. CN104967256A) and the prior art 4 (patent No. CN204794587) propose an air-gap-adjustable disc-type electric machine, which adopts a turbine electric machine to drive the axial movement of a bearing cover, so as to realize the axial movement of a rotor disc, and then realize the adjustment of the size of the air-gap of the electric machine. This method is feasible, but this method is only applicable to single-disc disc-type electric machines, and cannot realize the adjustment of the size of the air-gap for double-rotor single-stator or double-stator single-rotor disc-type electric machines due to the existence of double air-gaps.

[0006] Prior art 5 (patent number CN103944330A) and prior art 6 (patent number CN203827141U) use screw rods to control the axial displacement of the stator on both sides of the rotor disc of the double-stator single-rotor disc motor, so as to adjust the air gap size of the disc motor. Although this invention can adjust the air gap size, it cannot fix the relative position of the rotor disc and the stator disc on both sides in the axial direction, that is, it cannot guarantee that the air gap sizes on both sides of the rotor disc are equal. This way of adjusting the air gap is extremely easy to cause the air gap sizes on both sides of the rotor disc to be unequal. At the same time, this way of adjusting the air gap needs to set multiple screw rods along the circumference of the stator disc, and needs to have good consistency. In addition, this way of adjusting the air gap is difficult to achieve automatic control.

[0007] Prior art 7 (patent number CN209516751U) and prior art 8 (patent number CN209497329U) use the gas pressure of an external gas source to adjust the air gap size of the disc motor. Since the rotor disc is rotating, there must be a certain gap between its outer circle and the housing. Therefore, this method cannot adjust the air gap size of the disc motor by adjusting the gas pressure in the air gap.

[0008] Prior art 8 (patent number CN10528142A) proposes a disc permanent magnet coreless motor with adjustable air gap magnetic strength, which uses a worm to drive a thrust bearing sleeve to rotate, and cooperates with an intermediate end cover to realize the axial movement of the rotor disc. This invention has the following problems: first, this method can only adjust the single-sided air gap, and since the stator cannot move, the other air gap cannot be adjusted. Second, an additional intermediate end cover needs to be added inside the motor, which is very difficult to produce and manufacture.

[0009] In addition, the disc motor air gap adjustment control method mentioned in prior art 2 (patent number CN104993647A) uses three fixed point values, namely the minimum air gap value, the maximum air gap value and the constant air gap value, which cannot realize stepless speed regulation of the current electric vehicle motor or continuous pressure regulation of the steam turbine. This is the deficiency of the prior art. SUMMARY

[0010] The technical problem to be solved by the present application is to provide a double-rotor single-stator permanent magnet disc motor with adjustable air gap and a control method thereof, in view of the deficiencies of the prior art.

[0011] The scheme is realized through the following technical measures: a double-rotor single-stator permanent-magnet disc motor with adjustable air gap, comprising a casing, end covers fixedly connected to two ends of the casing, a motor shaft arranged in the casing, the motor shaft penetrating the end covers at two ends of the casing, a stator and two rotors mounted on the motor shaft, the two rotors being arranged on two sides of the stator, the stator being provided with a stator winding, each rotor comprising a rotor disc and a rotor disc fixed baffle fixedly connected to the rotor disc, the rotor disc being fixedly provided with a magnetic steel, the rotor disc fixed baffle being provided with a rotor disc fixed baffle ball groove, and the rotor disc fixed baffle ball groove being placed with a ball; the rotor disc fixed baffle being rotationally connected with an axial tension gear disc, the rotor disc fixed baffle ball groove being arranged in the axial tension gear disc, and the axial tension gear disc being provided with an axial tension gear disc ball groove matched with the rotor disc fixed baffle ball groove to arrange the ball; the axial tension gear disc being fixedly provided with an axial tension gear, and the axial tension gear disc being threadedly connected with the motor shaft; the rotor disc being fixedly mounted with a displacement motor, the displacement motor being drivingly connected with a displacement motor gear, and the displacement motor gear being in meshing transmission with the axial tension gear; both ends of the motor shaft being fixedly provided with a conductive copper ring, the end cover being fixedly provided with a brush capable of contacting the conductive copper ring, and the displacement motor being connected with the conductive copper ring through a wire.

[0012] Preferably, the rotor disc fixed baffle is fixedly connected with the rotor disc through a rotor disc fixing screw, and the rotor disc fixed baffle is connected with the motor shaft through a flat key.

[0013] Preferably, the axial tension gear disc comprises two half-ring structures, and the two half-ring structures are fixedly connected through an axial tension gear disc closing bolt.

[0014] Preferably, the rotor disc fixed baffle is provided with a displacement motor wire hole, the motor shaft is provided with a motor shaft threading hole, the motor shaft is provided with a motor shaft hollow hole through which an axis penetrates, the motor shaft threading hole is in communication with the motor shaft hollow hole, and the wire of the displacement motor is connected with the conductive copper ring through the displacement motor wire hole, the motor shaft threading hole and the motor shaft hollow hole.

[0015] Preferably, the motor shaft is provided with a motor shaft key groove, the flat key is arranged in the motor shaft key groove and cooperates with the rotor disc fixed baffle key groove, and the rotor disc fixed baffle key groove is arranged to prevent the rotor disc fixed baffle from rotating axially.

[0016] Preferably, the axial tension gear disc is provided with axial tension gear disc displacement threads, and the motor shaft is provided with motor shaft displacement threads matched with the axial tension gear disc displacement threads.

[0017] Preferably, the rotor disc fixing baffle is fixedly connected with the rotor disc through a rotor disc fixing screw.

[0018] A control method of the air gap adjustable double-rotor single-stator permanent magnet disc type motor, comprising the following steps:

[0019] S01 when it is needed to adjust the air gap size, controlling the displacement motor fixedly arranged on the two rotor discs, the displacement motor driving the axial tension gear to rotate through the displacement motor gear, and then driving the axial movement of the rotor disc, so as to realize the adjustment of the disc type motor air gap size;

[0020] S02 real-time detection of the disc type motor voltage test coil voltage, the voltage test coil being a number of turns coil pre-buried in the stator winding, if the voltage sizes of the stator two sides are not equal, then the displacement motor of the side with the gap to the target voltage is controlled and adjusted until the voltages of the two sides of the stator winding are equal and equal to the target voltage.

[0021] The application provides an air gap adjustable double-rotor single-stator permanent magnet disc type motor and a control method thereof, and has the following beneficial effects:

[0022] (1) Compared with the method for adjusting the air gap magnetic field by using the direct-axis current component of the stator winding, the application directly changes the air gap length by mechanical structure, without the need of the stator winding to provide the direct-axis current component, so that the motor efficiency is improved and the excitation current is saved.

[0023] (2) The application adopts the method for changing the air gap length when adjusting the air gap magnetic field, and compared with the method for adjusting the air gap magnetic field by using the direct-axis current component of the stator winding, the risk of permanent magnet demagnetization is greatly reduced.

[0024] (3) Compared with the method for adjusting the air gap magnetic field by using the direct-axis current component of the stator winding, the application has a larger air gap magnetic field adjustment range, that is, has a larger speed regulation or pressure regulation range for the motor or generator.

[0025] (4) the application adopts the method that small motor driving gear belt drives the rotor disc to move synchronously with the rotor, realizes the adjustment of the air gap size of the double-rotor single-stator disc type motor, the control method is to measure the motor test coil voltage in real time, controls the rotation of the small driving motor in real time according to the test coil voltage, and then adjusts the air gap size until the speed regulation or voltage stabilization requirement is met. The control mode is simple and easy to realize in engineering.

[0026] Therefore, compared with the prior art, the application has outstanding substantial characteristics and significant progress, and the beneficial effects of the implementation are also obvious. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the application, the drawings required to be used in the description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0028] Figure 1 is the overall structural diagram of the application;

[0029] Figure 2 is a schematic view of the rotor disc structure;

[0030] Figure 3 is a schematic view of the rotor baffle;

[0031] Figure 4 is an axial tension gear disc;

[0032] Figure 5 is an installation schematic view of the axial tension gear disc, the rotor disc and the rotor baffle;

[0033] Figure 6 is an installation schematic view of the motor shaft and the rotor baffle;

[0034] Figure 7 is a motor internal structure diagram;

[0035] Figure 8 is a permanent magnet disc type motor weak magnetic speed regulation control flow chart;

[0036] Figure 9 is a permanent magnet disc type motor weak magnetic speed regulation control flow chart.

[0037] In the figure: 1-rotor disc, 11-magnetic steel;

[0038] 2-displacement motor, 21-displacement motor gear, 22-displacement motor fixing screw;

[0039] 3-rotor disc fixed baffle, 31-rotor disc fixed baffle key groove, 32-rotor disc fixed screw, 33-rotor disc fixed baffle through hole, 34-displacement motor wire hole, 35-rolling ball, 36-rotor disc fixed baffle rolling ball groove;

[0040] 4-axial tension gear disc, 41-axial tension gear disc folding screw hole, 42-axial tension gear disc displacement thread, 43-axial tension gear disc rolling ball groove, 44-axial tension gear;

[0041] 5-motor shaft, 51-motor shaft threading hole, 52-motor shaft displacement thread, 53-motor shaft hollow hole, 54-motor shaft key groove, 55-flat key, 56-conductive copper ring;

[0042] 6-end cover;

[0043] 7-brush;

[0044] 8-stator, 81-winding;

[0045] 9-housing. DETAILED DESCRIPTION

[0046] In order to make the invention purpose, features, advantages of the present application more obvious and easy to understand, the following will use specific examples and drawings, the technical solutions of the present application are described clearly and completely, obviously, the following described examples are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the patent, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the patent protection.

[0047] As Figures 1-7As shown, an air gap adjustable double rotor single stator permanent magnet disc type motor includes a shell 9, both ends of the shell 9 are fixedly connected with end covers 6, a motor shaft 5 is arranged in the shell 9, both ends of the motor shaft 5 penetrate the end covers 6 at both ends of the shell 9, a stator 8 and two rotors are installed on the motor shaft 5, the two rotors are arranged on both sides of the stator 8, the stator 8 is provided with a stator winding 81, each rotor comprises a rotor disc 1 and a rotor disc fixed baffle 3 fixedly connected with the rotor disc 1, the rotor disc 1 is fixedly provided with a magnetic steel 11, the rotor disc fixed baffle 3 is provided with a rotor disc fixed baffle ball groove 36, and the rotor disc fixed baffle ball groove 36 is placed with a ball 35; the rotor disc fixed baffle 3 is rotationally connected with an axial tension gear disc 4, the rotor disc fixed baffle ball groove 36 is arranged in the axial tension gear disc 4, and the axial tension gear disc 4 is provided with an axial tension gear disc ball groove 43 matched with the ball 35 arranged in the rotor disc fixed baffle ball groove 36; the axial tension gear disc 4 is fixedly provided with an axial tension gear 44, and the axial tension gear disc 4 is threadedly connected with the motor shaft 5; the rotor disc 1 is fixedly provided with a displacement motor 2, the displacement motor 2 is drivingly connected with a displacement motor gear 21, the displacement motor gear 21 is in meshing transmission with the axial tension gear 44; both ends of the motor shaft 5 are fixedly provided with conductive copper rings 56, the conductive copper rings 56 are in interference fit with the motor shaft, the conductive copper rings 56 comprise a plurality of annular bodies, the annular bodies are insulated from each other and from the motor shaft 5, the end covers 6 are fixedly provided with brushes 7 which can contact the conductive copper rings 56, and the displacement motor 2 is connected with the conductive copper rings 56 through wires.

[0048] Further, the rotor fixed disc baffle 3 is fixedly connected with the rotor disc 1 through a rotor disc fixing screw 32, and the rotor disc fixed baffle 3 is connected with the motor shaft 5 through a flat key 55.

[0049] Further, the axial tension gear disc 4 comprises two half annular structures which are fixedly connected through an axial tension gear disc closing bolt 45.

[0050] Further, the rotor disc fixed baffle 3 is provided with a displacement motor wire hole 34, the motor shaft 5 is provided with a motor shaft threading hole 51 and a motor shaft hollow hole 53 through the axis, the motor shaft threading hole 51 is in communication with the motor shaft hollow hole 53, and the wires of the displacement motor 2 are connected with the conductive copper rings 56 through the displacement motor wire hole 34, the motor shaft threading hole 51 and the motor shaft hollow hole 53.

[0051] Further, the motor shaft 5 is provided with a motor shaft key groove 54, and the flat key 55 is arranged in the motor shaft key groove 54 and matched with the rotor disc fixed baffle key groove 31.

[0052] Further, the axial tension gear disc 4 is provided with axial tension gear disc displacement threads 42, and the motor shaft 5 is provided with motor shaft displacement threads 52 matched with the axial tension gear disc displacement threads 42.

[0053] Further, the rotor disc fixing baffle 3 is fixedly connected with the rotor disc 1 through rotor disc fixing screws 32.

[0054] A control method of a dual-rotor single-stator permanent-magnet disc motor with adjustable air gap, comprising the following steps:

[0055] S01, when it is necessary to adjust the size of the air gap, controlling the displacement motor 2 fixedly arranged on the two rotor discs 1, the displacement motor 2 driving the axial tension gear 44 to rotate through the displacement motor gear 21, and then driving the axial movement of the rotor disc 1, so as to realize the adjustment of the size of the air gap of the disc motor; S02, real-time detection of the voltage test coil voltage of the disc motor, the voltage test coil being a number of turns of coil pre-embedded in the stator winding 81, if the voltage sizes of the coils on both sides of the stator 8 are not equal, the displacement motor 2 on the side with a gap from the target voltage is controlled and adjusted until the voltages on both sides of the stator winding 81 are equal and equal to the target voltage.

[0056] The voltage sizes at both ends of the voltage test coil and the no-load back electromotive force of the motor have a certain proportional relationship (the proportional size is related to the number of turns of the test coil and the number of turns in series per phase), by measuring the voltage size of the test coil, the size of the motor back electromotive force at this time can be calculated according to the proportional relationship.

[0057] The control flow chart of the weak magnetic speed regulation of the dual-rotor single-stator permanent-magnet disc motor is as shown in Figure 8 The control flow chart of the output voltage adjustment of the dual-rotor single-stator permanent-magnet disc motor is as shown in Figure 9 . Figure 8 and Figure 9 U c1 and U c2 are respectively the voltages on the pre-embedded test coils of the stator windings on both sides, k is the ratio of the number of turns in series per phase to the number of turns of the pre-embedded coil, U VF is the maximum output voltage of the frequency converter, n is the current speed of the motor, n d is the target speed of the motor. ξ is a small number, which is generally defined according to the speed regulation or voltage regulation accuracy requirement. U2 is the output voltage of the generator, and U ref is the voltage value that the generator needs to stabilize.

[0058] The application proposes to change the air gap size of a double-rotor single-stator disc motor by mechanical structure, and then to realize the adjustment of the motor air gap magnetic field size, to realize the weak magnetic speed regulation of the motor or the output voltage adjustment function of the generator. Compared with the commonly used method of adjusting the air gap magnetic field by changing the direct current component of the stator winding, the energy is saved, the motor efficiency is improved, and a practical method is provided for the application of permanent magnet motor in the power generation field. In the specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other.

[0059] The above description of disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features, creative features disclosed herein.

Claims

1. A dual-rotor single-stator permanent magnet rotary disc motor with adjustable air gap, characterized in that: The device includes a housing (9), with end caps (6) fixedly connected to both ends of the housing (9). A motor shaft (5) is installed inside the housing (9), with both ends of the motor shaft (5) passing through the end caps (6) at both ends of the housing (9). A stator (8) and two rotors are mounted on the motor shaft (5), with the two rotors located on both sides of the stator (8). A stator winding (81) is provided on the stator (8). Each rotor includes a rotor disk (1) and a rotor disk fixing baffle (3) fixedly connected to the rotor disk (1). A magnet (11) is fixedly provided on the rotor disk (1). A rotor disk fixing baffle (3) has a rotor disk fixing baffle ball groove (36), in which a ball (35) is placed. An axial tension gear disk (4) is rotatably connected to the rotor disk fixing baffle (3). A ball groove (36) is provided in the axial tension gear disk (4). The axial tension gear disk (4) is provided with an axial tension gear disk ball groove (43) that cooperates with the ball groove (36) of the rotor disk fixing baffle to set the ball (35). An axial tension gear (44) is fixedly provided on the axial tension gear disk (4). The axial tension gear disk (4) is threadedly connected to the motor shaft (5). A displacement motor (2) is fixedly installed on the rotor disk (1). The displacement motor (2) drives the displacement motor gear (21) connected to it. The displacement motor gear (21) meshes with the axial tension gear (44). A conductive copper ring (56) is fixedly provided at both ends of the motor shaft (5). A brush (7) that can contact the conductive copper ring (56) is fixedly provided on the end cover (6). The displacement motor (2) is connected to the conductive copper ring (56) through a wire.

2. The air gap adjustable dual-rotor single-stator permanent magnet motor according to claim 1, characterized in that: The rotor disk fixing baffle (3) is fixedly connected to the rotor disk (1) by rotor disk fixing screws (32), and the rotor disk fixing baffle (3) is connected to the motor shaft (5) by a flat key (55).

3. The air gap adjustable dual-rotor single-stator permanent magnet motor according to claim 1, characterized in that: The axial tension gear disk (4) includes two semi-annular structures, which are fixedly connected by axial tension gear disk closing bolts (45).

4. The air gap adjustable dual-rotor single-stator permanent magnet motor according to claim 1, characterized in that: The rotor disk fixing baffle (3) is provided with a displacement motor wire hole (34), the motor shaft (5) is provided with a motor shaft through hole (51), the motor shaft (5) is provided with a through-hole (53), the motor shaft through hole (51) and the motor shaft hollow hole (53) are connected, and the wire of the displacement motor (2) is connected to the conductive copper ring (56) through the displacement motor wire hole (34), the motor shaft through hole (51) and the motor shaft hollow hole (53).

5. The air gap adjustable dual-rotor single-stator permanent magnet motor according to claim 2, characterized in that: The motor shaft (5) has a motor shaft keyway (54), and the flat key (55) is set in the motor shaft keyway (54) and cooperates with the rotor disk fixing baffle keyway (31).

6. The air gap adjustable dual-rotor single-stator permanent magnet motor according to claim 1, characterized in that: The axial tension gear disk (4) is provided with an axial tension gear disk displacement thread (42), and the motor shaft (5) is provided with a motor shaft displacement thread (52) that cooperates with the axial tension gear disk displacement thread (42).

7. The air gap adjustable dual-rotor single-stator permanent magnet motor according to claim 1, characterized in that: The rotor disk fixing baffle (3) and the rotor disk (1) are fixedly connected by rotor disk fixing screws (32).

8. A control method for a dual-rotor single-stator permanent magnet disc motor with adjustable air gap according to any one of claims 1-7, characterized in that: Includes the following steps: S01 When it is necessary to adjust the air gap size, control the displacement motor (2) fixedly installed on the two rotor discs (1). The displacement motor (2) drives the axial tension gear (44) to rotate through the displacement motor gear (21), thereby driving the rotor disc (1) to move axially and realize the adjustment of the air gap size of the disc motor. S02 Real-time detection of disc motor voltage test coil voltage. The voltage test coil is a coil of several turns pre-embedded in the stator winding (81). If the voltage of the coils on both sides of the stator (8) is not equal, the displacement motor (2) on the side with the difference in target voltage is controlled and adjusted until the voltage on both sides of the stator winding (81) is equal and equal to the target voltage.

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