Axial magnetic modulation dual-stator permanent magnet synchronous motor and magnetic modulation control method thereof

Abstract

The present invention provides an axial magnetic modulation dual-stator permanent magnet synchronous motor and a magnetic modulation control method thereof, comprising a radial stator, an axial stator and a rotor, wherein the axial stator is placed on one side of the radial stator, and both the axial stator and the radial stator are equipped with armature windings; the axial stator is connected to the end of the rotor, the rotor is sleeved in the radial stator, the length of the rotor is greater than the length of the radial stator, and both ends of the rotor extend outside the radial stator; the magnetic flux generated by the rotor permanent magnet is divided into a radial main magnetic circuit and an axial main magnetic circuit, and the magnetic circuits in the two directions are in parallel. By adjusting the parallel magnetic circuit, the magnetic flux distribution of the motor and the operating state of the motor can be adjusted, which can reduce the risk of demagnetization, effectively utilize the end space of the motor, and eliminate end leakage magnetic flux.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors and relates to an axial magnetic modulation dual-stator permanent magnet synchronous motor and a magnetic modulation control method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Speed-regulating permanent magnet synchronous motors can be divided into two types: surface rotor structure and built-in rotor structure, depending on the different ways of placing the permanent magnets on the rotor:

[0004] In a surface-type rotor structure, the permanent magnets are machined into an arc shape and fixed directly to the outer surface of the rotor. The permanent magnets directly face the motor's air gap, and the magnetic flux generated by the permanent magnets directly passes through the air gap into the stator to form effective magnetic flux. Since the permanent magnets in a surface-type rotor structure are directly mounted on the rotor surface, they need to be machined into an arc shape that matches the rotor and air gap to ensure a uniform air gap. Due to the brittle nature of permanent magnet materials, their precise machining is complex, requiring high processing technology and high cost. In addition, since the permanent magnets are directly mounted on the rotor surface, the centrifugal force during motor operation requires that the permanent magnets be wrapped with a non-weft tape to prevent them from falling off and being damaged during high-speed rotor rotation. Since the air gap flux density of the permanent magnet is proportional to its width, when the width of the permanent magnet is determined, the motor's no-load air gap flux density is also determined. In actual design, the width of the motor's permanent magnets is restricted by the no-load air gap flux density. Since the permanent magnets directly face the motor's air gap, when the motor requires weak magnetic field expansion control, i.e. ... d When the control is not equal to 0, the magnetic flux generated by the armature winding will directly pass through the permanent magnet, and the permanent magnet faces the risk of irreversible demagnetization; because the magnetic permeability of the permanent magnet material is very close to that of air, the reactance of the d-axis and q-axis in the surface rotor structure is equal. When the motor is running, the torque is generated only by the interaction between the permanent magnet magnetic field and the armature magnetic field, and no reluctance torque is generated. The torque density and power density of the motor are lower than those of the built-in rotor structure; the surface rotor structure cannot place a starting cage on the outside of the rotor, and the motor cannot achieve self-starting.

[0005] In the built-in rotor structure, permanent magnets are embedded in the rotor core according to certain requirements, and the permanent magnets generate magnetic flux in the core. The embedding forms of permanent magnets in the built-in rotor structure are diverse, and the permanent magnets can be combined in series and parallel according to different requirements to achieve a magnetic concentration effect to meet actual performance needs. Compared with the surface rotor structure, the permanent magnets in the built-in rotor structure are not directly placed on the rotor surface, but are embedded in the rotor core in a certain form. The permanent magnets do not directly face the air gap of the motor. The permanent magnets are fixed by the permanent magnet slots in the rotor and do not need to be fixed with weftless belts. The rotor mechanical structure has good integrity and the motor has high reliability when rotating at high speeds. The permanent magnets can achieve a magnetic concentration effect through flexible combinations of series and parallel connections, and can obtain an air gap flux density that is much larger than that of the surface rotor structure. The motor power density and torque density are higher than those of the surface rotor structure. The motor pole arc coefficient and the air gap flux density have no direct relationship and can be set independently during design. Under overload conditions, since the permanent magnets do not directly face the air gap, the risk of demagnetization can be reduced.

[0006] However, when the built-in rotor structure is performing magnetic modulation control, if the d-axis magnetic flux generated by the armature winding passes through the permanent magnets of the motor, it will cause irreversible demagnetization of the permanent magnets. If the d-axis magnetic flux generated by the armature winding is not closed by the permanent magnets, the magnetic field generated by the d-axis current forces more rotor magnetic flux to pass through the ends and end covers of the motor for closure, significantly increasing the leakage flux of the motor. Moreover, since the magnetic resistance of the motor ends is usually much larger than the air gap magnetic resistance, the d-axis current required for magnetic weakening is relatively large, which significantly increases the cost of the motor power inverter and the copper loss of the winding. Summary of the Invention

[0007] In order to solve the above problems, the present invention proposes an axial magnetic modulation dual-stator permanent magnet synchronous motor and a magnetic modulation control method thereof. The present invention has a built-in rotor, and the magnetic flux generated by the rotor permanent magnet is divided into a radial main magnetic circuit and an axial main magnetic circuit. The magnetic circuits in the two directions are in parallel. By adjusting the parallel magnetic circuit, the motor flux distribution and the motor operating state can be adjusted, which can reduce the risk of demagnetization, effectively utilize the end space of the motor, and eliminate end leakage magnetic flux.

[0008] According to some embodiments, the present invention adopts the following technical solutions:

[0009] An axial magnetic modulation dual-stator permanent magnet synchronous motor comprises a radial stator, an axial stator and a rotor, wherein the axial stator is placed on one side of the radial stator, and both the axial stator and the radial stator are equipped with armature windings;

[0010] The axial stator is connected to the end of the rotor, the rotor is sleeved in the radial stator, the length of the rotor is greater than the length of the radial stator, and both ends of the rotor extend outside the radial stator;

[0011] The rotor includes a first rotor and a second rotor arranged side by side, the first rotor and the second rotor being an annular structure, a plurality of permanent magnets being distributed circumferentially on the annular structure, a rib structure corresponding to the rotor being provided between adjacent permanent magnets, and magnetically conductive spokes being connected to the rib structure, the magnetically conductive spokes of the first rotor and the magnetically conductive spokes of the second rotor having opposite magnetic polarities, all of the magnetically conductive spokes being provided on the inner side of the annular structure and in a direction radial to the stator arrangement, and at least a portion of the magnetically conductive spokes being provided through and between the first rotor and the second rotor;

[0012] The permanent magnets are combined in series and parallel to generate magnetic poles in the radial and axial directions on the rotor. The radial and axial main magnetic fluxes generated by the radial and axial magnetic poles interact with the magnetic field generated by the corresponding armature windings to generate torque. By controlling the current applied to the armature windings, the torque is dynamically adjusted and the motor operating state is dynamically controlled.

[0013] As an optional embodiment, the first rotor and the second rotor have the same number of rib structures, which is the number of pole pairs of the motor. The rib structures are connected to the yokes of the corresponding rotors, and the rib structures of the first rotor and the second rotor are staggered by an angle of 180 / the number of pole pairs of the motor.

[0014] Furthermore, the number of pole pairs of the motor is greater than or equal to one.

[0015] As an optional embodiment, the length of the magnetic conductive spokes of the first rotor is greater than the length of the magnetic conductive spokes of the second rotor, and both extend to the axial stator provided on the second rotor side.

[0016] Furthermore, the magnetic spokes are fan-shaped and match the inner edge of the rotor.

[0017] As an optional embodiment, the armature winding is a single-layer winding or a double-layer winding, wherein the number of motor phases is greater than or equal to three.

[0018] As an optional embodiment, a radial air gap is formed between the radial magnetic pole and the radial stator, and an axial air gap is formed between the axial magnetic pole and the axial stator.

[0019] As an optional implementation, the radial magnetic circuit and the axial magnetic circuit are parallel magnetic circuits. By adjusting the current angles of the armature windings corresponding to the radial stator and the axial stator, the parallel magnetic circuit is adjusted and the magnetic field distribution state of the motor is changed.

[0020] As a further limited implementation method, by adjusting the current angle of the armature windings corresponding to the radial stator and the axial stator, the proportion of the d-axis demagnetization current component of the corresponding armature winding is changed. When the d-axis demagnetization current is applied to the radial stator armature winding of the motor, the magnetic flux generated by the rotor permanent magnet enters more into the axial stator, the constant power operating speed range of the motor is widened, and it has a certain torque output capacity; when the d-axis demagnetization current is applied to the axial stator armature winding of the motor, the magnetic flux generated by the rotor permanent magnet enters more into the radial stator, and the torque output capacity of the motor is increased.

[0021] A magnetic regulation control method dynamically adjusts the torque and dynamically controls the operating state of the motor by controlling the current applied to the armature winding;

[0022] By adjusting the current angles of the armature windings corresponding to the radial stator and the axial stator, the proportion of the d-axis demagnetizing current component of the corresponding armature winding is changed, thereby changing the magnetic field distribution state of the motor.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The motor of the present invention is provided with an axial stator on one side of the rotor end and a radial stator in the radial direction, forming a radial and axial parallel magnetic circuit. The total amount of magnetic flux generated by the permanent magnets on the motor rotor is constant and has different directions according to the radial and axial directions of the motor. By adjusting the d-axis current components in the stators with different radial and axial directions, different motor magnetic field distribution states are obtained, thereby improving the motor operating performance and obtaining better starting and weak magnetic operation capabilities.

[0025] The parallel magnetic circuits of the motor rotor of the present invention are "rotor ribs" and "rotor magnetic spokes". The rotor magnetic spokes conduct magnetism toward one side of the axial end face of the motor and form axial magnetic poles on one side of the axial end face of the rotor. The rotor parallel magnetic circuits are all designed using the inherent support structure of the rotor, which reduces the design of the additional parallel magnetic circuit mechanical structure and has a relatively simple structure. The motor is provided with an axial stator and a radial stator, and has a parallel magnetic circuit of an axial magnetic circuit and a radial magnetic circuit, which effectively utilizes the end space of the motor and eliminates end magnetic leakage. By applying the d-axis current component to the armature winding on the axial and radial stators, the magnetic flux of the magnetic circuit branch can be controlled, thereby controlling the magnetic flux distribution state of the entire motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0027] Figure 1 This is a schematic diagram of the overall structure of the motor of the present invention;

[0028] Figure 2 、3 A schematic three-dimensional diagram of the motor rotor structure of the present invention;

[0029] Figure 4 This is a structural diagram of the axial stator of the motor of the present invention;

[0030] In the figure, 1. first rotor, 2. second rotor, 3. permanent magnet, 4. first rotor rib structure, 5. second rotor rib structure, 6. magnetic spokes connecting the first rotor to the ribs, 7. magnetic spokes connecting the second rotor to the ribs, 8. radial stator, 9. radial stator armature winding, 10. radial stator teeth, 11. radial stator slots, 12. axial stator, 13. axial stator slots, 14. axial stator teeth, 15. axial stator armature winding. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0033] like Figure 1 As shown, an axial magnetic modulation dual-stator permanent magnet synchronous motor includes three main components: a radial stator 8, an axial stator 12, and a rotor. The rotor is built into the radial stator 8 and is coaxial with the stator. The axial stator 12 is placed on one side of the rotor end. The radial and axial stators are equipped with armature windings.

[0034] The rotor is composed of two identical rotor sections (i.e., a first rotor 1 and a second rotor 2). Each rotor section has p staggered rib structures connected to a rotor yoke. p is the number of pole pairs of the motor. The ribs of the two rotor sections are staggered by a certain angle. The degree of stagger is related to the number of poles and is 360 / 2p degrees. This ensures that the ribs of the two rotor sections have opposite magnetic polarities.

[0035] The two rotor end shafts are designed with magnetic spokes of different radii. Since the magnetic spokes are connected to the ribs of the two rotors, the magnetic spokes of the two rotors have opposite magnetic polarities. The magnetic spokes of the two rotors extend to the rotor end face on the axial stator 12 side, forming axial rotor magnetic poles with alternating polarity, which correspond to the axial stator 12.

[0036] like Figure 2 、 Figure 3As shown, the rotor is provided with permanent magnets, which generate magnetic flux on the rotor through the "magnetic focusing effect". A part of the permanent magnets passes through the rotor yoke and directly faces the radial air gap, forming radial magnetic poles, and the other part passes through the "rotor ribs-rotor magnetic spokes" to reach the rotor ends, forming axial magnetic poles.

[0037] The magnetic flux of the radial poles and axial poles of the motor enters the radial stator 8 and the axial stator 12 through the radial air gap and the axial air gap, and interacts with the magnetic flux generated by the armature winding on the corresponding stator to form the motor radial and axial main magnetic flux, and generate driving torque or form different motor magnetic field distribution patterns through magnetic modulation of the armature winding.

[0038] When the motor is running, different currents are applied to the armature windings on the radial and axial stators 12 to dynamically adjust the main magnetic flux and driving torque of the motor during operation, thereby achieving dynamic control of the motor operation.

[0039] In some embodiments, the radial stator 8 is made of stacked silicon steel sheets, and the radial stator 8 includes stator slots, stator teeth and a stator yoke. The armature winding is placed in the radial stator slots 11; the axial stator 12 is made of stacked silicon steel sheets, and the axial stator 12 includes stator slots, stator teeth and a stator yoke. The armature winding is placed in the axial stator slots 13.

[0040] In some embodiments, the rotor has rotor slots, in which permanent magnets are placed. The permanent magnets are connected in series and parallel to achieve a "magnetic focusing effect" and generate magnetic poles in the radial and axial directions of the rotor.

[0041] In some embodiments, the radial magnetic poles and the axial magnetic poles face the radial stator 8 and the axial stator 12 of the motor respectively, and there are radial and axial air gaps between the radial-axial magnetic poles and the radial-axial stators respectively. The radial-axial main magnetic flux generated by the radial-axial magnetic poles interacts with the magnetic field generated by the armature winding to generate torque. The entire rotor is composed of two identical rotor sections. The two rotors have an alternating rib structure. The rib structure of each rotor section is connected to the magnetic spokes on the rotor end shaft, and the two rotor sections have the same fan-shaped magnetic spokes. The magnetic spokes extend beyond the side end of the axial stator 12 of the motor to form axial magnetic poles. The axial magnetic poles correspond to the axial stator 12, and there is an axial air gap between the axial magnetic poles of the rotor and the axial stator 12.

[0042] In some embodiments, the magnetic flux generated by the permanent magnets on the rotor is divided into two parts, entering the radial stator 8 and axial stator 12 of the motor respectively, forming radial main magnetic flux and axial main magnetic flux, with the radial and axial magnetic circuits being in parallel. By adjusting the current angles of the radial and axial armature windings, the parallel magnetic circuits can be adjusted, thereby changing the magnetic field distribution of the motor.

[0043] The permanent magnet is a high-performance permanent magnet material, such as neodymium iron boron, rare earth cobalt, or a low-performance permanent magnet material, such as alnico or ferrite.

[0044] When a d-axis demagnetizing current is applied to the radial stator armature winding 9 of the motor, more magnetic flux generated by the rotor permanent magnet enters the axial stator 12, the constant power operating speed range of the motor is widened, and it has a certain torque output capacity; when a d-axis demagnetizing current is applied to the axial stator 12 armature winding of the motor, more magnetic flux generated by the rotor permanent magnet enters the radial stator 8, and the torque output capacity of the motor is increased.

[0045] The proportion of each d-axis demagnetizing current component can be controlled by controlling the current angle of the radial and axial stator armature windings, so that the motor can obtain different magnetic field distribution states and operating states.

[0046] A torque drive method for an axially magnetically modulated dual-stator permanent magnet synchronous motor is disclosed. The method applies q-axis current to the radial and axial stator armature windings, interacting with the rotor's main magnetic field to generate driving torque. The method applies d-axis current to the radial and axial stator armature windings to reduce the amplitude of the magnetic flux in one branch and indirectly increase the amplitude of the magnetic flux in the other branch. The method specifically includes:

[0047] When the motor is starting or operating normally, the motor end axial stator 12 applies a d-axis demagnetizing current, and the radial stator 8 applies a q-axis current to generate a driving torque, or both the radial stator 8 and the axial stator 12 of the motor apply a q-axis current;

[0048] When the motor needs to perform weak magnetic operation, a d-axis demagnetization current is applied to the radial stator 8 of the motor, and a q-axis current is applied to the axial stator 12 at the end of the motor. The magnetic flux generated by the permanent magnets on the rotor enters the axial stator 12 through the "rotor ribs-rotor magnetic spokes-axial air gap". Torque can also be generated through the axial stator 12 under high-speed operation, thereby widening the constant power operation range of the motor.

[0049] In some embodiments, various performances are achieved by reasonably designing various parameters of the motor, such as the air gap length and the number of turns of the stator armature winding, according to the rated speed, rated torque and specific performance requirements of the motor.

[0050] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. An axially magnetically modulated dual-stator permanent magnet synchronous motor, characterized in that: It includes a radial stator, an axial stator and a rotor, wherein the axial stator is placed on one side of the radial stator, and both the axial stator and the radial stator are installed with armature windings; The axial stator is connected to the end of the rotor, the rotor is sleeved in the radial stator, the length of the rotor is greater than the length of the radial stator, and both ends of the rotor extend outside the radial stator; The rotor includes a first rotor section and a second rotor section arranged side by side. The first rotor and the second rotor are annular structures. A plurality of permanent magnets are distributed circumferentially on the annular structure. A rib structure corresponding to the rotor is provided between adjacent permanent magnets. Magnetic spokes are connected to the rib structure. The magnetic spokes of the first rotor and the magnetic spokes of the second rotor have opposite magnetic polarities. All magnetic spokes are arranged on the inner side of the annular structure and in a direction radial to the stator arrangement. At least a portion of the magnetic spokes are provided between the first rotor and the second rotor. The permanent magnets are combined in series and parallel to generate magnetic poles in the radial and axial directions on the rotor. The radial and axial main magnetic fluxes generated by the radial and axial magnetic poles interact with the magnetic fields generated by the corresponding armature windings to generate torque. By controlling the current applied to the armature windings, the torque is dynamically adjusted and the motor operation state is dynamically controlled. The first rotor and the second rotor have the same number of rib structures, which is the same as the number of pole pairs of the motor. The rib structures are connected to the yokes of the corresponding rotors. The rib structures of the first rotor and the second rotor are staggered by an angle of 180° / the number of pole pairs of the motor. The length of the magnetically conductive spokes of the first rotor is greater than the length of the magnetically conductive spokes of the second rotor, and both extend to the axial stator arranged on the side of the second rotor.

2. The axially magnetically modulated dual-stator permanent magnet synchronous motor according to claim 1, characterized in that: The number of pole pairs of the motor is greater than or equal to one.

3. The axially magnetically modulated dual-stator permanent magnet synchronous motor according to claim 1, characterized in that: The magnetic spokes are fan-shaped and match the inner edge of the rotor.

4. The axially magnetically modulated dual-stator permanent magnet synchronous motor according to claim 1, characterized in that: The armature winding is a single-layer winding or a double-layer winding, wherein the number of phases of the motor is greater than or equal to three.

5. The axially magnetically modulated dual-stator permanent magnet synchronous motor according to claim 1, characterized in that: There is a radial air gap between the radial magnetic poles and the radial stator, and there is an axial air gap between the axial magnetic poles and the axial stator.

6. The axially magnetically modulated dual-stator permanent magnet synchronous motor according to claim 1, characterized in that: The radial magnetic circuit and the axial magnetic circuit are parallel magnetic circuits. By adjusting the current angles of the armature windings corresponding to the radial stator and the axial stator, the parallel magnetic circuit can be adjusted and the magnetic field distribution state of the motor can be changed.

7. The axially magnetically modulated dual-stator permanent magnet synchronous motor according to claim 6, characterized in that: By adjusting the current angles of the armature windings corresponding to the radial stator and the axial stator, the proportion of the d-axis demagnetization current component of the corresponding armature winding is changed. When the d-axis demagnetization current is applied to the radial stator armature winding of the motor, more magnetic flux generated by the rotor permanent magnet enters the axial stator, the constant power operating speed range of the motor is widened, and the motor has a certain torque output capacity; when the d-axis demagnetization current is applied to the axial stator armature winding of the motor, more magnetic flux generated by the rotor permanent magnet enters the radial stator, and the torque output capacity of the motor is increased.

8. A magnetic modulation control method, based on an axial magnetic modulation dual-stator permanent magnet synchronous motor according to any one of claims 1 to 7, characterized in that: By controlling the current applied to the armature winding, the torque is dynamically adjusted and the operating state of the motor is dynamically controlled; By adjusting the current angles of the armature windings corresponding to the radial stator and the axial stator, the proportion of the d-axis demagnetizing current component of the corresponding armature winding is changed, thereby changing the magnetic field distribution state of the motor.

Images