Disc motor and control method thereof

Abstract

The present invention provides a disc motor, comprising a first stator core and a second stator core arranged in the axial direction, and a rotor arranged between the first stator core and the second stator core; the rotor comprises a disc support member and a plurality of magnets arranged circumferentially around the disc support member, the magnets comprising a magnet body made of non-memory magnets, and an embedding opening provided on the magnet body and penetrating in the width direction thereof, wherein a magnet-supplementing magnet made of memory magnets is arranged in the embedding opening. By inputting a pulse current into the magnet-supplementing magnet, a variable magnetic field can be generated, which is synthesized with the constant magnetic field generated by the magnet body to meet the magnetic field performance under different rotation speed requirements of the disc motor. The present invention also provides a control method for the disc motor.

Description

Technical Field

[0001] The present invention relates to the technical field of disc motors, and more particularly to a disc motor and a control method thereof. Background Art

[0002] Permanent magnet synchronous motors have been widely used in industries such as industry, aerospace, etc. due to their high power density, high efficiency, and simple structure. However, due to the limitations of the characteristics of permanent magnet materials, traditional permanent magnet motors have problems such as difficulty in adjusting the air gap magnetic field and difficulty in achieving a wide speed regulation range.

[0003] Electric vehicles are driven by permanent magnet motors. When running at high speeds, weak magnetic control is generally used due to the voltage limitation of the inverter, resulting in high copper loss. In order to ensure the stability of motor performance, traditional permanent magnet motors must have a certain degree of anti-demagnetization ability, requiring that the permanent magnets will not produce irreversible demagnetization within the normal working range and in harsh working environments.

[0004] This means that the thickness of the permanent magnet must be thick enough to resist the demagnetizing magnetomotive force generated by the armature winding. Therefore, when designing a traditional permanent magnet motor, its structure makes the permanent magnet unable to be re-magnetized. Once magnetized, it will remain in its magnetized state during the service life of the motor.

[0005] The variable flux motor can adjust the air gap magnetic field through online adjustment of DC magnetizing current or d-axis current according to the load and speed, so as to make the motor run efficiently. Unlike the traditional permanent magnet motor, which needs to apply continuous d-axis current during weak magnetic operation, due to the characteristics of the permanent magnet material used, applying a short pulse current can change the magnetization state of the permanent magnet and conveniently adjust the air gap magnetic field.

[0006] The invention patent with the patent number CN107040064A discloses a dual-stator axial magnetic field flux switching hybrid permanent magnet memory motor, including two stators with salient pole structures and a rotor with salient pole structure. The two stators have the same structure and are respectively recorded as the first stator and the second stator. The two stators are arranged relative to each other, and the rotor is coaxially arranged between the two stators. One of the two stators only uses NdFeB permanent magnets, and the other stator only uses AlNiCo permanent magnets. The permanent magnets on a single stator are alternately magnetized along the circumferential direction. The magnetization directions of the permanent magnets in the relative positions of the two stators are opposite, and the two permanent magnets are in series structure in the magnetic circuit. The stator using NdFeB permanent magnets is used to generate a constant magnetic flux, and the stator using AlNiCo permanent magnets generates a variable magnetic flux for adjusting the air gap magnetic field. The present invention proposes to adopt a series structure hybrid permanent magnet excitation mode, so that the motor retains the characteristics of higher power density of traditional permanent magnet motors, while having the characteristics of wide speed operation range and high efficiency of memory motors.

[0007] However, in the hybrid permanent magnet memory motor, the AC winding and the regulating winding are separated, and the rotor magnet is transferred to the stator to avoid the stuck phenomenon caused by the fixed position of the rotor magnet when the regulating current is applied. However, it causes the stator to be split, and the difficulty of stator manufacturing increases. The separation of the AC winding and the regulating winding uses more copper, and the winding manufacturing is also more complicated.

[0008] The invention patent with patent number CN104617727B discloses a variable flux reluctance motor, including a stator and a rotor located inside the stator. The rotor includes a plurality of rotor poles that are mirror images of each other on the left and right sides with their respective center lines as axes. The distance between the outer surface of each rotor pole and the inner surface of the stator increases from the center line to both sides. The variable flux reluctance motor can ensure that torque pulsation is reduced under the premise of small torque density loss.

[0009] However, in the variable flux reluctance motor, the AC armature coil and the excitation regulating coil are separated, which increases the difficulty of winding production. The power density, noise and torque pulsation of the reluctance motor are not as good as those of the permanent magnet synchronous motor.

[0010] Therefore, how to optimize the working structure of the variable flux motor is a problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0011] In view of this, the present invention provides a disc-type motor to optimize the working structure of the variable flux motor; the present invention also provides a control method for the disc-type motor.

[0012] In order to achieve the above object, the present invention provides the following technical solutions:

[0013] A disc-type motor comprises a first stator core and a second stator core arranged in an axial direction, and a rotor arranged between the first stator core and the second stator core;

[0014] The rotor includes a disc-type support component and a plurality of magnets arranged circumferentially around the disc-type support component, wherein the magnets include a magnet body made of a non-memory magnetic steel, and an embedding opening opened on the magnet body and penetrating through the width direction thereof, wherein a supplementary magnet made of a memory magnetic steel is arranged in the embedding opening.

[0015] Preferably, in the above-mentioned disc motor, the embedding openings include a plurality of embedding openings arranged at intervals along the radial direction of the magnetic steel, and the magnetizing magnetic steel is arranged in each of the embedding openings.

[0016] Preferably, in the above-mentioned disc motor, the magnetic steel body is divided into a plurality of spaced-apart sub-magnetic steel bodies by the embedding opening, the magnetic steel is arranged as the complementary magnet along its radial inner side, and the magnetic steel is arranged with the sub-magnetic steel body along its radial outer side.

[0017] Preferably, in the above-mentioned disc motor, the sub-magnetic steel body and the supplementary magnetic steel have the same width along the radial direction of the magnetic steel.

[0018] Preferably, in the above-mentioned disc motor, the complementary magnetism steel includes a first complementary magnetism steel arranged on the radial inner side of the magnetic steel and a second complementary magnetism steel arranged in the middle of the magnetic steel; the sub-magnetic steel body includes a first sub-magnetic steel body and a second sub-magnetic steel body arranged alternately with the first complementary magnetism steel and the second complementary magnetism steel.

[0019] Preferably, in the above-mentioned disc motor, the first complementary magnetizing magnetic steel, the first sub-magnetic steel body, the second complementary magnetizing magnetic steel and the second sub-magnetic steel body have the same curvature.

[0020] Preferably, the above-mentioned disc motor further includes a charging and demagnetizing coil electrically connected to the first magnetizing magnetic steel and the second magnetizing magnetic steel for inputting a pulse current.

[0021] A method for controlling a disc motor comprises the following steps:

[0022] 1) When the disc motor runs below the base speed, control i d =0,i q Generate electromagnetic torque;

[0023] 2) When the disk motor is running at a speed above the base speed, a pulsed field-weakening current is inputted in a direction opposite to the direction of the magnetic supplementary steel, the magnitude of which is determined by the maximum magnetic flux that can be achieved at the first predetermined speed of the disk motor. When the magnetic supplementary steel stabilizes at the magnetic field performance required for the disk motor to achieve the first predetermined speed, the pulsed field-weakening current is removed, and the i is controlled. d =0.

[0024] Preferably, in the above-mentioned control method of the disc motor, the following steps are further included:

[0025] 3) When the disk motor needs to slow down to below the base speed, a pulse magnetization current is input with the same current direction as the direction of the magnetizing magnetic steel. The magnitude of the pulse magnetization current is determined by the maximum magnetic flux that can be achieved at the second predetermined speed of the disk motor. When the magnetizing magnetic steel stabilizes at the magnetic field performance required by the disk motor to achieve the second predetermined speed, the pulse magnetization current is removed and the i is controlled. d =0.

[0026] Preferably, in the above-mentioned control method of the disc motor, the i d and the i q The magnitude and direction are obtained by the Parker transform.

[0027] The disc motor provided by the present invention comprises a first stator core and a second stator core arranged in the axial direction, and a rotor arranged between the first stator core and the second stator core; the rotor comprises a disc support member and a plurality of magnetic steels arranged circumferentially around the disc support member, the magnetic steels comprising a magnetic steel body made of non-memory magnetic steel, and an embedding opening provided on the magnetic steel body and running through the width direction thereof, and a magnetizing magnetic steel made of memory magnetic steel is arranged in the embedding opening. The magnetic steels are arranged circumferentially around the disc support member, and the two constitute a rotor frame supported between the first stator core and the second stator core, the magnetic steels are in a fan-shaped structure, the magnetic steel body made of non-memory magnetic steel generates a constant magnetic field, the magnetic steel body is provided with an embedding opening running through the width direction thereof, and the magnetizing magnetic steel with memory characteristics is installed in the embedding opening, when the motor is working, by inputting pulse current to the magnetizing magnetic steel, the magnetizing magnetic steel can generate a variable magnetic field, which is synthesized with the constant magnetic field generated by the magnetic steel body, so as to meet the magnetic field performance under different speed requirements of the disc motor. The magnetic steel body and the complementary magnetic steel are embedded in a combination, with low assembly difficulty and simple preparation process. Memory-characteristic magnetic steel is used to generate variable magnetic steel. The winding method of the coil is not changed. Magnetic pulses can be provided through the stator coils on the first stator core and the second stator core, which reduces the difficulty of coil winding, thereby improving the process structure of the variable flux motor as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the arrangement structure of the stator core and the rotor in the disc-type motor provided by the present invention;

[0030] Figure 2 for Figure 1 Schematic diagram of the magnetic steel structure of the middle rotor. DETAILED DESCRIPTION

[0031] The invention discloses a disc-type motor, which optimizes the working structure of a variable flux motor; the invention also provides a control method for the disc-type motor.

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0033] like Figure 1 and Figure 2 As shown, Figure 1 A schematic diagram of the arrangement structure of the stator core and the rotor in the disc-type motor provided by the present invention; Figure 2 for Figure 1 Schematic diagram of the magnetic steel structure of the middle rotor.

[0034] Figure 1 The rotor 4 shown is only used to show the schematic diagram of the arrangement structure of the magnetic steel 41, and the structure for fixing the disc-type support member is not shown. The multiple magnetic steels 41 on the rotor 4 are distributed in a circular shape. Figure 2 Used to indicate the specific structure of magnetic steel.

[0035] The present embodiment provides a disc-type motor, comprising a first stator core 1 and a second stator core 2 arranged along the axial direction, and a rotor 4 arranged between the first stator core 1 and the second stator core 2; the rotor 4 comprises a disc-type supporting member and a plurality of magnetic steels 41 arranged circumferentially around the disc-type supporting member, the magnetic steels 41 comprising a magnetic steel body 411 made of magnetic steel with non-memory characteristics, and an embedding opening opened on the magnetic steel body 411 and penetrating in the width direction thereof, wherein a complementary magnetic steel 410 made of magnetic steel with memory characteristics is arranged in the embedding opening. The magnetic steel 41 is arranged circumferentially around the disc support member, and the two together form a rotor 4 supported between the first stator core 1 and the second stator core 2. The magnetic steel is in a fan-shaped structure, and the magnetic steel body 411 made of non-memory magnetic steel generates a constant magnetic field. The magnetic steel body 411 is provided with an embedding opening that runs through its width direction, and the complementary magnetic steel 410 with memory characteristics is installed in the embedding opening. When the motor is working, by inputting pulse current to the complementary magnetic steel 410, it can generate a variable magnetic field, which is synthesized with the constant magnetic field generated by the magnetic steel body to meet the magnetic field performance under different speed requirements of the disc motor. The magnetic steel body and the complementary magnetic steel are embedded in combination, with low assembly difficulty and simple preparation process. The variable magnetic steel is generated by using magnetic steel with memory characteristics, and the winding method of the coil is not changed. The stator coil 3 on the first stator core 1 and the second stator core 2 can provide magnetic pulses, which reduces the difficulty of coil winding, thereby using the process structure of the variable flux motor as a whole.

[0036] In a specific embodiment of the present case, the embedding openings include a plurality of embedding openings arranged at intervals along the radial direction of the magnetic steel 41, and each embedding opening is provided with a magnetizing magnetic steel 410. The embedding openings include a plurality of embedding openings arranged at intervals along the radial direction of the magnetic steel 41, which direction is the radial arrangement direction of the magnetic steel 41 along the rotor 4, and the magnetic steel 41 is provided with a magnetizing magnetic steel 410 in each embedding opening.

[0037] Specifically, the magnetic steel body 411 is divided into a plurality of spaced-apart sub-magnetic steel bodies (421, 431) by an embedding opening, the magnetic steel is arranged as a complementary magnetic steel 410 along its radial inner side, and the magnetic steel 41 is arranged as a sub-magnetic steel body 421 along its radial outer side.

[0038] That is, the magnetic steel body 411 is arranged to be composed of a plurality of sub-magnetic steel bodies (421, 431), and an embedding opening for embedding the complementary magnet steel is formed between two adjacent sub-magnetic steel bodies (421, 431). Since the embedding openings are arranged at intervals on the magnetic steel body 411, the sub-magnetic steel bodies (421, 431) and the complementary magnet steel 410 are arranged in an alternating manner, so that the sub-magnetic steel bodies (421, 431) are evenly arranged in the radial direction of the magnetic steel 41, and the complementary magnet steel 410 is arranged in the embedding opening and is also evenly distributed in the radial direction of the magnetic steel 41, thereby ensuring that the magnetic field generated by the magnetic steel is evenly distributed along the radial direction of the rotor, thereby optimizing the motor performance.

[0039] In a specific embodiment of the present case, the sub-magnetic steel body (421, 431) and the supplementary magnet 410 have the same width along the radial direction of the magnet 41. By making the sub-magnetic steel body (421, 431) and the supplementary magnet 410 have the same width along the radial direction of the magnet 41, it is ensured that the sub-magnetic steel body (421, 431) generates a uniform magnetic field along the radial direction of the magnet 41. When the supplementary magnet 410 is excited by a pulse magnetic current, the magnetic field generated by the supplementary magnet 410 arranged alternately with the sub-magnetic steel body (421, 431) can uniformly strengthen or weaken the constant magnetic field of the magnet body 411, thereby ensuring the stability of the motor working structure and avoiding the jamming phenomenon of the rotor caused by the adjustment pulse current.

[0040] In a specific embodiment of the present case, the supplementary magnet 410 includes a first supplementary magnet 430 disposed on the radial inner side of the magnet 41 and a second supplementary magnet 420 disposed in the middle of the magnet 41; the sub-magnetic steel body (421, 431) includes a first sub-magnetic steel body 431 and a second sub-magnetic steel body 421 arranged alternately with the first supplementary magnet 430 and the second supplementary magnet 420. This embodiment provides a preferred solution for the rotor magnet, the supplementary magnet 410 includes a first supplementary magnet 430 and a second supplementary magnet 420, the sub-magnetic steel body 411 includes a first sub-magnetic steel body 431 and a second sub-magnetic steel body 421, the first supplementary magnet 430 is located on the radial inner side of the magnet 41, and the second sub-magnetic steel body 421 is located on the radial outer side of the magnet 41, and the magnetic field is uniform in the radial direction of the magnet through the alternating arrangement structure.

[0041] Preferably, the first supplementary magnet 430, the first sub-magnet body 431, the second supplementary magnet 420 and the second sub-magnet body 421 have the same curvature. To adapt to the disc-shaped structure of the rotor 4, a plurality of magnets 41 are evenly distributed around the rotor 4, and each magnet 41 is in a fan-shaped structure. Since the supplementary magnet 410 and the magnet body 411 are arranged along the width direction of the magnet 41, the supplementary magnet and the magnet body are arranged to have the same curvature along the radial direction of the magnet, and the two are embedded to form a fan-shaped magnet structure.

[0042] In a specific embodiment of the present case, a charging and demagnetizing coil electrically connected to the first and second magnetizing magnetic steels for inputting pulse current is also included. The magnetizing magnetic steel is a magnetic steel with memory characteristics, and can generate different magnetic field strengths through magnetic pulses. The charging and demagnetizing coils are arranged in the disk motor, and pulse magnetic currents of the magnetizing magnetic steel are input through the charging and demagnetizing coils, thereby realizing the excitation of the magnetic field of the magnetic steel with memory characteristics, which is combined with the constant magnetic field generated by the magnetic steel body to meet the magnetic field strength requirements of the disk motor at different base speeds.

[0043] Based on the disc motor provided in the above embodiment, the present case also provides a control method of the disc motor, including the steps of:

[0044] 1) When the disc motor runs below the base speed, control i d =0,i q Generates electromagnetic torque.

[0045] During the operation of the motor, the magnetic fields of the magnetic steel body and the supplementary magnet steel combine to form a constant magnetic field. By changing the size of the pulse magnetic current of the supplementary magnet steel, the size of the magnetic field generated by the supplementary magnet steel can be changed through its memory characteristics, thereby adjusting the magnetic field strength of the constant magnetic field.

[0046] The constant magnetic field is orthogonal to the rotating magnetic field generated by the stator AC coil to generate a rotating torque. The three-phase AC current i u ,i v ,i w Parker transformation can be transformed into the following relationship:

[0047]

[0048] Among them, i d Parallel to the constant magnetic field generated by the magnetic steel, strengthening or weakening the constant magnetic field;

[0049] i q Orthogonal to the constant magnetic field, electromagnetic torque is generated;

[0050] The base speed of the disc motor refers to the rated speed of the disc motor. When the disc motor runs below the base speed, the constant magnetic field generated by the magnetic steel body is qDirectional current cutting produces a constant electromagnetic torque, which can meet the working requirements of the motor.

[0051] At this time, control i d = 0, the magnetic field generated by the magnet is only the constant magnetic field generated by the non-memory magnet. q The constant magnetic field generated by cutting the non-memory magnetic steel can generate electromagnetic torque, which meets the working requirements of the disc motor at the base speed.

[0052] The relationship between the motor's back electromotive force ε and the motor speed n is as follows:

[0053] ε=4.44K dp NfΦ,

[0054] f = np / 60,

[0055] So, ε=4.44K dp NpnΦ / 60,

[0056] K dp The motor winding coefficient, N is the number of series turns per phase of the motor, p is the number of motor pole pairs, and Φ is the air gap flux of the motor.

[0057] When the motor is manufactured, its winding coefficient, number of series turns per phase and number of pole pairs are all determined. The permanent magnet produces a constant magnetic field. When there is no external adjustment, the air gap flux is also determined. Therefore, the back electromotive force of the motor increases with the increase of motor speed.

[0058] When the motor reaches a certain speed, such as the base speed, that is, the rated speed, the back electromotive force of the motor is equal to the external voltage. At this time, the speed of the motor cannot be increased any more. To increase the speed of the motor, the air gap flux can only be reduced. By changing the current angle θ through the controller, different i d , by i d The increase or decrease of the magnetic field performance of the magnetizing steel is adjusted to achieve the purpose of adjusting the air gap flux of the motor.

[0059] 2) When the disk motor is running above the base speed, a pulsed field-weakening current is inputted in the opposite direction of the magnetic field of the magnetic supplementary steel. The magnitude of the pulsed field-weakening current is determined by the maximum magnetic flux that can be achieved at the first predetermined speed of the disk motor. When the magnetic supplementary steel stabilizes at the magnetic field performance required for the disk motor to reach the first predetermined speed, the pulsed field-weakening current is removed and i is controlled. d =0.

[0060] The memory-based magnet steel is used to meet the variable flux requirements of the disc motor. When the disc motor meets the requirements of operating above the base speed, the pulse weak magnetic current is removed to control i d = 0, that is, after the magnetizing steel generates a magnetic field of a predetermined strength, there is no need to provide i d .id The removal time is adjusted according to the characteristics of the magnetic field excitation of the complementary magnet steel by the current, i d The size of i is adjusted according to the magnetic field performance required by the magnetizing steel to meet the first predetermined speed of the disc motor. The first predetermined speed is the current target speed of the disc motor. When the magnetizing steel reaches a stable magnetic field performance, control i d =0, at this time, there is no need to input the pulse weak magnetic current. By removing the pulse weak magnetic current, the magnetizing magnetic steel can utilize its memory characteristics to generate a constant magnetic field with the magnetic steel body.

[0061] In a specific embodiment of the present case, the steps are also included:

[0062] 3) When the disk motor needs to slow down to run below the base speed, a pulse magnetizing current with the same current direction as the magnetic field direction of the magnetizing steel is input. The magnitude of the pulse magnetizing current is determined by the maximum magnetic flux that can be achieved at the second predetermined speed of the disk motor. When the magnetizing steel stabilizes at the magnetic field performance required for the disk motor to reach the second predetermined speed, the pulse magnetizing current is removed and i is controlled. d =0.

[0063] The control process of the disc motor from above the base speed to below the base speed is equivalent to the above process. By inputting a pulse magnetizing current, the pulse magnetizing current and the magnetic field of the magnetic steel with memory characteristics are weakened and adjusted. The magnetic field strength of the magnetic steel can be reduced to the initial state by controlling the magnitude of the pulse magnetizing current. Only the constant magnetic field generated by the magnetic steel body and i q Generate a constant electromagnetic torque to meet the working requirements below the base speed. The magnitude of the pulse magnetizing current can be controlled according to the magnetic field strength required at the second predetermined speed. The second predetermined speed is the current target speed of the disc motor. The pulse magnetizing current can be directly provided to remove the magnetic field of the supplementary magnet steel, and the electromagnetic torque is generated only through the magnet steel body. The removal timing of the pulse magnetizing current can be controlled according to the response time of the supplementary magnet steel.

[0064] The disc motor provided in this embodiment adopts the present invention under all working conditions. d =0 control, i q It is used to generate electromagnetic torque. Only when the air gap flux needs to be changed, the current angle θ is changed to make i d Generate instantaneous pulse current, and i q The electromagnetic torque generated still exists, so the motor can run smoothly, adding i d After the instantaneous pulse current, the magnetizing steel has memory characteristics. The magnetizing steel is a permanent magnet with memory characteristics. The magnetic properties are stable at the magnetic field performance required at this speed. Remove i d , the disc motor enters the preset speed working state.

[0065] The above embodiment provides a method for the disc motor to transition from below the base speed to above the base speed, and from above the base speed to below the base speed. d Specifically, the disc motor also includes two states: when the speed is above the base speed, the motor transitions to a higher speed, and when the speed is reduced from a higher speed to above the base speed. This process is still controlled by adjusting i d The increase or decrease of the control can be specifically divided into:

[0066] 1. The disc motor works below the base speed (rated speed). At this time, the back electromotive force is less than the external voltage. q It only needs to provide the current required for the torque;

[0067] 2. The disc motor switches from below base speed to above base speed. At this time, the back electromotive force must exceed the external voltage. Apply i d , generating instantaneous pulse weak magnetic current, after which the permanent magnet with memory magnetic steel has stable magnetic field performance at the required speed. d Can be removed, i q It is only necessary to provide the current required for the torque at this time;

[0068] 3. The disc motor switches from a speed above the rated speed to a higher speed, the process is the same as step 2;

[0069] 4. The disc motor speed switches from above the base speed to below the base speed. When the disc motor works below the base speed, the back electromotive force is smaller than the external voltage, and there is no need to reduce the air gap flux. In order to reduce i q , apply i d , generating an instantaneous pulse magnetizing current, so that the magnetizing magnetic steel returns to its initial magnetic state. After that, the magnetic properties of the permanent magnet with memory magnetic steel stabilize at the magnetic field performance required at this speed. At this time, i d Can be removed, i q It is only necessary to provide the current required for the torque at this time;

[0070] 5. The disc motor switches from a higher speed to above the base speed. The disc motor decreases from a higher speed to a lower speed, but does not run below the base speed. As the speed decreases, the back electromotive force decreases, and the air gap flux can increase to reduce the i that generates the torque. q , apply i d , generating instantaneous pulse magnetizing current, increasing the air gap magnetic flux, after which the magnetic properties of the permanent magnet with memory magnetic steel stabilize at the magnetic field performance required at this speed. At this time, i d Can be removed, i q It is only necessary to provide the current required for the torque at that time.

[0071] In summary, by adopting a structure in which the rotor magnetic steel is set to be a non-memory magnetic steel and a magnetic steel with memory characteristics arranged alternately, when the rotation speed of the disc motor needs to be adjusted, id =0 The air gap magnetic field of the disc motor is adjusted online. The pulse current increases the magnetic field performance of the magnetic steel with memory characteristics, reduces the copper loss during weak magnetic field, and improves the efficiency of the motor in the high-speed area. In the low-speed area, non-memory magnetic steel is still used, and the efficiency is unchanged.

[0072] In a specific embodiment of the present case, i d and i q The size is controlled by the current angle of the input disc motor. d and i q The current is controlled by the pulse magnetic coil. In this case, the pulse magnetic coil and the AC coil are the same coil. The current angle is adjusted by the control device to control i d and i q The size can be controlled accurately, the response time is fast, and the jamming phenomenon can be further avoided.

[0073] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A disc motor, characterized in that: The invention comprises a first stator core and a second stator core arranged in an axial direction, and a rotor arranged between the first stator core and the second stator core; The rotor comprises a disc-type support member and a plurality of magnetic steels arranged circumferentially around the disc-type support member, wherein the magnetic steel comprises a magnetic steel body made of non-memory magnetic steel, and an embedding opening opened on the magnetic steel body and penetrating in the width direction thereof, wherein a supplementary magnetic steel made of memory magnetic steel is arranged in the embedding opening; The embedding openings include a plurality of magnetizing steel bodies arranged at intervals along the radial direction of the magnet, and the magnetizing steel is disposed in each of the embedding openings; the magnet body is divided into a plurality of sub-magnetic steel bodies arranged at intervals by the embedding openings, the magnet is disposed at the inner side of the magnet along the radial direction, and the sub-magnetic steel body is disposed at the outer side of the magnet along the radial direction; the magnetizing steel includes a first magnetizing steel body disposed at the inner side of the magnet and a second magnetizing steel body disposed at the middle of the magnet; the sub-magnetic steel body includes a first sub-magnetic steel body and a second sub-magnetic steel body arranged alternately with the first magnetizing steel body and the second magnetizing steel body; The disk motor also includes a charging and demagnetizing coil electrically connected to the first magnetic supplementary steel and the second magnetic supplementary steel for inputting a pulse current; When the disk motor is working, a pulse current is input into the magnetizing magnetic steel to generate a variable magnetic field, which is synthesized with the constant magnetic field generated by the magnetic steel body to meet the magnetic field performance of the disk motor under different rotation speed requirements.

2. The disc motor according to claim 1, characterized in that: The sub-magnetic steel body and the supplementary magnetizing steel have the same width along the radial direction of the magnetic steel.

3. The disc motor according to claim 1, characterized in that: The first supplementary magnetizing steel, the first sub-magnetic steel body, the second supplementary magnetizing steel and the second sub-magnetic steel body have the same curvature.

4. A control method for a disc motor, characterized in that: The disc motor is a disc motor as claimed in any one of claims 1 to 3, comprising the steps of: 1) When the disc motor runs below the base speed, control i d =0,i q Generate electromagnetic torque; 2) When the disk motor is running at a speed above the base speed, a pulsed weak magnetic current with a current direction opposite to that of the supplementary magnetic steel is input to the supplementary magnetic steel, and the magnitude of the pulsed weak magnetic current is determined by the maximum magnetic flux that can be achieved at the first predetermined speed of the disk motor. When the supplementary magnetic steel is stabilized at the magnetic field performance required for the disk motor to reach the first predetermined speed, the pulsed weak magnetic current is removed, and i is controlled d =0.

5. The control method of the disk motor according to claim 4, characterized in that: Also includes the steps: 3) When the disk motor needs to slow down to below the base speed, a pulse magnetization current is input with the same current direction as the direction of the magnetizing magnetic steel. The magnitude of the pulse magnetization current is determined by the maximum magnetic flux that can be achieved at the second predetermined speed of the disk motor. When the magnetizing magnetic steel stabilizes at the magnetic field performance required by the disk motor to achieve the second predetermined speed, the pulse magnetization current is removed and the i is controlled. d =0.

6. The control method of the disk motor according to claim 4, characterized in that: The i d and the i q The magnitude and direction are obtained by the Parker transform.

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