Asymmetric magnetic pole variable flux variable inductance inverse salient pole permanent magnet motor
By designing an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor, and utilizing multi-layer permanent magnets and magnetic barrier structures, combined with variable flux poles, the motor achieves high-efficiency operation under a wide range of operating conditions. This solves the problems of torque reduction and demagnetization risk during high-speed operation, and improves the safety and reliability of the motor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-03-10
- Publication Date
- 2026-05-12
AI Technical Summary
When the reverse salient pole permanent magnet motor is running at high speed, it requires a direct shaft demagnetizing current to reduce the permanent magnet air gap flux, which leads to a decrease in the motor output torque and makes it difficult to operate efficiently over a wide range of operating conditions.
A non-symmetric permanent magnet motor with variable magnetic flux and variable inductance is designed. It uses multi-layer permanent magnets and magnetic barriers in the same layer to construct a variable inductance magnetic pole unit. Combined with variable magnetic flux magnetic poles, the leakage magnetic bridge saturation is controlled by adjusting the permanent magnet air gap flux and armature current, so as to achieve efficient operation under multiple working conditions without demagnetizing current.
Without relying on demagnetizing current, it improves the high-speed performance and low-speed high-torque output capability of the motor, widens the speed regulation range, reduces the risk of permanent magnet demagnetization, and improves the safety and reliability of the motor.
Smart Images
Figure CN121813791B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of motors, and particularly relates to an asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor. Background Technology
[0002] In traditional positive salient permanent magnet motors, both the permanent magnet and the magnetic barrier are located on the direct axis, resulting in lower magnetic reluctance in the quadrature axis path, exhibiting an L-shaped magnetic field. d <L q It exhibits positive salient pole ratio characteristics. To utilize reluctance torque, its motor operating range is generally located in the second quadrant (i... d <0, i q >0). This type of motor has good driving characteristics at low speeds and can achieve high torque output, but at high speeds, a large amount of field weakening current is required to widen the motor speed range, which increases the risk of irreversible demagnetization of the permanent magnet.
[0003] In recent years, a class of materials with inverse salient polarity (L...) has been studied. d >L q The magnetic field-enhanced motor achieves L-axis extension by placing the magnetic barrier on the quadrature axis. d >L q The reverse salient pole structure. Compared with the traditional positive salient pole permanent magnet motor, its motor operating range is located in the first quadrant (i... d >0, i q >0), by applying a positive direct-axis current, the reluctance torque can be effectively utilized, avoiding the injection of a large amount of weak magnetic current, thereby significantly reducing the risk of irreversible demagnetization of the permanent magnet, and exhibiting good driving performance in low-speed, high-torque output applications.
[0004] However, in order to achieve multi-condition operation and widen the speed range of the reverse salient pole permanent magnet motor, under the condition of limited bus voltage, a direct-axis demagnetizing current still needs to be applied during high-speed operation of the reverse salient pole permanent magnet motor to reduce the permanent magnet air gap flux and counteract the rise in back electromotive force. At this time, the operating point of the reverse salient pole permanent magnet motor shifts from the first quadrant to the second quadrant (i... d <0, i q >0), the original direct-axis magnetizing current is converted into direct-axis demagnetizing current, which causes the reluctance torque to become negative, and the motor output torque drops significantly, which is not conducive to widening the speed regulation range in the high-speed range.
[0005] Therefore, how to ensure the high-speed operation performance of the reverse salient pole permanent magnet motor while eliminating the dependence on the direct shaft demagnetizing current and achieving efficient operation over a wide range of operating conditions remains a key challenge that urgently needs to be overcome in the design of this type of motor. Summary of the Invention
[0006] The purpose of this invention is to at least partially solve the above-mentioned technical problems, and to provide an asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor, which can achieve efficient operation under multiple working conditions without relying on demagnetizing current.
[0007] This invention provides an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor, comprising a stator structure and an asymmetric pole rotor. The stator structure is sleeved on the outer periphery of the asymmetric pole rotor. The asymmetric pole rotor includes a rotor core and variable flux magnetic pole units and variable inductance magnetic pole units alternately arranged on the rotor core. Each variable flux magnetic pole unit includes a magnetic barrier and two structurally identical variable flux magnetic poles. The radial centerline of the magnetic barrier is the direct axis of the variable flux magnetic pole unit. The symmetry centerline of the variable flux magnetic pole is the quadrature axis of the variable flux magnetic pole unit. Each variable flux magnetic pole includes a first leakage magnetic barrier arranged on its symmetry centerline, two second leakage magnetic barriers symmetrically arranged on both sides of its symmetry centerline, and two symmetrically arranged... The first permanent magnet is arranged in a figure-eight shape on both sides of its symmetrical center line, with the opening side facing the inner ring of the rotor core. The first permanent magnet has a first end magnetic barrier at the first end near the inner ring of the rotor core. Two second leakage magnetic barriers form a discontinuous fan-shaped magnetic barrier. The discontinuous fan-shaped magnetic barrier is located between the first leakage magnetic barrier and the outer ring of the rotor core, and its outer end corresponds to the second end of the first permanent magnet. The variable inductance magnetic pole unit includes two structurally identical variable inductance magnetic poles symmetrically arranged on both sides of its direct axis. The variable inductance magnetic pole includes N second permanent magnets arranged radially on the cross axis of the variable inductance magnetic pole unit and second end magnetic barriers arranged at both ends of each second permanent magnet. The second end magnetic barriers extend to the outer ring of the rotor core, and N is an integer greater than or equal to 1.
[0008] In some embodiments, the angle bisector of the direct axis of two adjacent variable flux magnetic pole units coincides with the direct axis of the variable inductance magnetic pole unit between them.
[0009] In some embodiments, the quadrature axis direction of the variable flux magnetic pole unit and the direct axis direction of the variable inductance magnetic pole unit are both aligned with the stator winding at i d The direction of the quadrature magnetic field generated when the quadrature current is applied under the =0 control is consistent with that of the variable flux magnetic pole unit and the quadrature direction of the variable inductance magnetic pole unit. The direction of the direct axis magnetic field generated when only the direct axis current is applied to the stator winding is consistent with that of the direct axis magnetic field generated when only the direct axis current is applied to the stator winding.
[0010] In some embodiments, both the first permanent magnet and the second permanent magnet are cuboids and magnetized along the thickness direction; in the variable magnetic flux pole unit, the two first permanent magnets near the magnetic barrier are magnetized in the same direction, either pointing towards the air gap or away from the air gap, while the first permanent magnets in the same variable magnetic flux pole are magnetized in opposite directions, one pointing towards the air gap and the other away from the air gap; the second permanent magnet is magnetized in the same direction and the same as the first permanent magnet near the variable inductance pole.
[0011] In some embodiments, the first permanent magnets on both sides of the magnetic barrier are arranged in a V-shape with an included angle of α. pm1 Satisfying 90° < α pm1 <150°.
[0012] In some embodiments, the cross-section of the magnetic barrier is oblong, and its radial centerline coincides with the direct axis of the variable magnetic flux pole unit.
[0013] In some embodiments, N second permanent magnets are placed in parallel at equal intervals along the radial direction.
[0014] In some embodiments, when the asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor is not supplied with armature current, the variable flux pole has a first leakage magnetic path and a second leakage magnetic path; the first leakage magnetic path starts from the first permanent magnet away from the direct axis of the variable flux pole unit, passes sequentially through the first leakage magnetic bridge, the first permanent magnet close to the direct axis and the second leakage magnetic bridge, and finally returns to the first permanent magnet away from the direct axis to form a closed loop; the second leakage magnetic path starts from the first permanent magnet away from the direct axis of the variable flux pole unit, passes sequentially through the first leakage magnetic bridge, the first permanent magnet close to the direct axis and the radially inner iron core of the first leakage magnetic barrier, and finally returns to the first permanent magnet away from the direct axis to form a closed loop; wherein, the first leakage magnetic bridge is located between the radially outer side of the discontinuous sector magnetic barrier and the outer ring of the rotor iron core; the second leakage magnetic bridge is located between the radially inner side of the discontinuous sector magnetic barrier and the radially outer side of the first leakage magnetic barrier.
[0015] In some embodiments, the first leakage magnetic bridge and the second leakage magnetic bridge have the same radial width.
[0016] In some embodiments, the asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor has a first main magnetic flux path and a second main magnetic flux path; wherein, the first main magnetic flux path starts from the first permanent magnet near the direct axis of the variable flux magnetic pole unit, passes through the first permanent magnet away from the direct axis, passes through the air gap into the stator structure, and finally returns to the asymmetric magnetic pole rotor to form a closed loop; the second main magnetic flux path starts from the second permanent magnet near the inner ring of the rotor core, passes radially through other second permanent magnets, passes through the air gap into the stator structure, and finally returns to the asymmetric magnetic pole rotor to form a closed loop.
[0017] The asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to embodiments of the present invention has at least one of the following advantages:
[0018] 1. This invention constructs a variable inductance magnetic pole unit by setting multiple layers of permanent magnets and magnetic barriers in the same layer. This unit has multiple layers of magnetic barriers on the quadrature-axis magnetic circuit to suppress quadrature-axis inductance, while the direct-axis magnetic circuit has no additional magnetic barriers or permanent magnets, thereby forming a direct-axis inductance greater than the quadrature-axis inductance (L). d >L q This paper describes a reverse salient pole motor structure. Based on this, a variable flux pole unit is introduced. By adjusting the permanent magnet air gap flux, the motor can achieve field weakening and speed increase at high speeds without injecting a negative direct-axis demagnetizing current, thus avoiding the output capacity reduction caused by the negative reluctance torque introduced by the demagnetizing current. Simultaneously, the variable inductance pole unit further increases the quadrature-axis reluctance through multiple layers of magnetic barriers, effectively suppressing the quadrature-axis inductance as the quadrature-axis current increases, and widening the difference between the direct and quadrature-axis inductance (L). d -L q This enhances the reluctance torque output capability at low speeds. The synergistic effect of the variable flux magnetic poles and the variable inductance magnetic poles enables the motor to operate efficiently across the entire speed range without relying on demagnetizing current, thus meeting the multi-condition requirements of low-speed high torque and high-speed wide speed range.
[0019] 2. During high-speed operation, the air gap flux of the permanent magnet is adjusted online by coordinating the double-layer leakage magnetic barrier (discontinuous sector-shaped magnetic barrier and first leakage magnetic barrier) in the variable flux magnetic pole with the figure-eight-shaped first permanent magnet, and by controlling the saturation degree of the leakage magnetic bridge using armature current. As the rotational speed increases, the air gap flux adaptively decreases with increasing speed, and the rise in back electromotive force is effectively suppressed. That is, the rotational speed can be increased without injecting demagnetizing current, which fundamentally reduces the risk of the permanent magnet being subjected to reverse magnetic field impact and significantly improves the permanent magnet's resistance to irreversible demagnetization.
[0020] 3. The three layers of magnetic barriers and embedded parallel permanent magnets in the variable inductance poles can dynamically adjust the quadrature and direct axis inductance parameters according to load changes, optimize the torque output capability under different working conditions, and work together with the variable flux poles to further broaden the constant power speed regulation range of the motor.
[0021] 4. In the present invention, the asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor, when unloaded or lightly loaded, a portion of the permanent magnet flux is directly closed inside the rotor through the leakage flux path, which reduces the effective magnetic flux passing through the air gap and correspondingly reduces the back EMF, thus exhibiting low no-load back EMF characteristics. It can significantly suppress short-circuit current without sacrificing overload capacity, further improving the safety and reliability of this type of motor. Attached Figure Description
[0022] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which:
[0023] Figure 1 The structure of an asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to an embodiment of the present invention is shown;
[0024] Figure 2 It shows Figure 1 The stator structure shown is in an asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor.
[0025] Figure 3 It shows Figure 1 The diagram shows a partial structure of the asymmetric pole rotor in an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor.
[0026] Figure 4 It shows Figure 1 The first and second leakage magnetic paths of the second variable flux magnetic pole of the variable flux magnetic pole unit of the asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor are shown.
[0027] Figure 5 It shows Figure 1 The first main flux path of the asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor is shown.
[0028] Figure 6 It shows Figure 1 The second main flux path of the asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor is shown.
[0029] Figure 7 It shows Figure 1 The simulated no-load flux distribution waveform of the asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor is shown in the stator winding without current flowing through it.
[0030] Figure 8 It shows Figure 1 The simulated load flux distribution waveform of the asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor is shown when a rated current of 12A is applied to the stator winding;
[0031] Figure 9 It shows Figure 1 The curves showing the variation of permanent magnet air gap flux linkage, direct-axis inductance, and quadrature-axis inductance of an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor with the magnitude of armature current flowing through the stator winding are shown.
[0032] Figure 10 It shows Figure 1 The curve shown is a curve showing the change in electromagnetic torque of an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor as a function of the current angle of the armature current flowing through the stator winding. Detailed Implementation
[0033] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof.
[0034] See Figure 1 This illustration shows the structure of an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor according to an embodiment of the present invention. The asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor includes a stator structure 1 and an asymmetric pole rotor 3. The stator structure 1 is sleeved on the outer periphery of the asymmetric pole rotor 3; an air gap 2 is left between the radially inner side of the stator structure 1 and the radially outer side of the asymmetric pole rotor 3. The asymmetric pole rotor 3 includes a rotor core and variable flux magnetic pole units and variable inductance magnetic pole units alternately arranged on the rotor core. The angle bisector of the direct axis of two adjacent variable flux magnetic pole units coincides with the direct axis of the variable inductance magnetic pole unit located between these two variable flux magnetic pole units. The cross-axis direction of the variable flux magnetic pole unit and the direct axis direction of the variable inductance magnetic pole unit are both perpendicular to the stator winding at i d The direction of the quadrature-axis magnetic field generated when a quadrature-axis current is applied under =0 control is consistent with that of the variable flux magnetic pole unit; the direct axis direction of the variable inductance magnetic pole unit and the quadrature axis direction are both consistent with the direction of the direct axis magnetic field generated when only a direct axis current is applied to the stator winding. For example, Figure 1 The asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor shown has 2 variable flux pole units and 2 variable inductance pole units.
[0035] See Figure 2 The stator structure 1 includes stator teeth 1-3, stator yoke 1-1, and stator winding 1-2, wherein the stator yoke 1-1 is located outside the stator teeth 1-3, and the stator winding 1-2 is wound on the stator teeth 1-3. The stator winding 1-2 adopts a distributed integer slot winding distribution form.
[0036] See Figure 3 , showed Figure 1 The diagram illustrates the structure of a variable flux pole unit in an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor. This variable flux pole unit includes a magnetic barrier 3-1 and two identical variable flux poles. The magnetic barrier 3-1 is positioned on the direct axis of the variable flux pole unit. Preferably, the cross-section of the magnetic barrier 3-1 is oblong, and its radial centerline coincides with the direct axis of the variable flux pole unit. The two variable flux poles are symmetrically positioned on either side of the direct axis of the variable flux pole unit. The two variable flux poles have identical structures. Specifically, the two variable flux poles in this variable flux pole unit are designated as the first variable flux pole and the second variable flux pole, respectively.
[0037] See Figure 3The first variable flux magnetic pole includes a first leakage magnetic barrier 3-4, a discontinuous sector magnetic barrier 3-2, a first permanent magnet 3-6, and a first permanent magnet 3-7. The discontinuous sector magnetic barrier 3-2 is composed of two identical second leakage magnetic barriers. The first permanent magnets 3-6 and 3-7 are symmetrically arranged on both sides of the first leakage magnetic barrier 3-4 in a figure-eight pattern, with their opening sides facing the inner ring of the rotor core. A first end magnetic barrier 3-10 is provided at the end of each of the first permanent magnets 3-6 and 3-7 closest to the inner ring of the rotor core. The radial centerline of the first leakage magnetic barrier 3-4 is the cross axis of the variable flux magnetic pole unit. The discontinuous sector magnetic barrier 3-2 is located between the first leakage magnetic barrier 3-4 and the outer ring of the rotor core, and the two ends of the discontinuous sector magnetic barrier 3-2 furthest from the cross axis of the variable flux magnetic pole unit are referred to as the outer ends. The two outer ends of the discontinuous sector-shaped magnetic barrier 3-2 correspond to the second ends of the first permanent magnet 3-6 and the first permanent magnet 3-7, with gaps between them. The radial outer side of the discontinuous sector-shaped magnetic barrier 3-2 forms a first leakage magnetic bridge 3-17 with the outer ring of the rotor core; the radial inner side of the discontinuous sector-shaped magnetic barrier 3-2 forms a second leakage magnetic bridge 3-18 with the radial outer side of the first leakage magnetic barrier 3-4. In this first variable flux pole, the first permanent magnet 3-6 and the first permanent magnet 3-7 are both cuboids, magnetized along the thickness direction, and magnetized in opposite directions, one pointing towards the air gap and the other away from the air gap.
[0038] like Figure 3 As shown, the second variable flux magnetic pole includes a first leakage magnetic barrier 3-5, a discontinuous sector-shaped magnetic barrier 3-3 formed by two second leakage magnetic barriers, and first permanent magnets 3-8 and 3-9 symmetrically arranged on both sides of the first leakage magnetic barrier 3-5 in a figure-eight pattern with their opening sides facing the inner ring of the rotor core. The ends of the first permanent magnets 3-8 and 3-9 closest to the rotor core are designated as the first ends, and each of the first ends of the first permanent magnets 3-8 and 3-9 is provided with a first end magnetic barrier 3-10. The radial centerline of the first leakage magnetic barrier 3-5 is the cross axis of the variable flux magnetic pole unit. The discontinuous sector-shaped magnetic barrier 3-3 is located between the first leakage magnetic barrier 3-5 and the outer ring of the rotor core, and the two ends of the discontinuous sector-shaped magnetic barrier 3-3 furthest from the cross axis of the variable flux magnetic pole unit are designated as the outer ends. The two outer ends of the discontinuous sector-shaped magnetic barrier 3-3 correspond to the second ends of the first permanent magnets 3-8 and 3-9, with gaps between them. The radial outer side of the discontinuous sector-shaped magnetic barrier 3-3 forms a first leakage magnetic bridge 3-20 with the outer ring of the rotor core; the radial inner side of the discontinuous sector-shaped magnetic barrier 3-3 forms a second leakage magnetic bridge 3-19 with the radial outer side of the first leakage magnetic barrier 3-5. In this second variable flux pole, the first permanent magnets 3-8 and 3-9 are both cuboids, magnetized along their thickness direction, with opposite magnetization directions, one pointing towards the air gap and the other away from the air gap. Figure 3 In the variable magnetic flux pole unit shown, the two first permanent magnets 3-7 and 3-8, which are close to the magnetic barrier, are magnetized in the same direction and both are away from the air gap.
[0039] In some embodiments of the present invention, the radial widths of the first leakage magnetic bridge 3-17 and the first leakage magnetic bridge 3-20 are both l. c1 Satisfying 1mm < l c1 <3mm, the radial width of the second leakage magnetic bridge 3-18 and the second leakage magnetic bridge 3-19 are both l c2 Satisfying 1mm < l c2 <2mm. Preferably, l c1 =l c2 .
[0040] In some embodiments of the present invention, the first permanent magnets on both sides of the magnetic barrier are arranged in a V-shape with an included angle of α. pm1 Satisfying 90° < α pm1 <150°. Specifically, the first permanent magnet 3-7 and the first permanent magnet 3-8 are arranged in a V-shape, with an included angle of α. pm1 Satisfying 90° < α pm1 <150°.
[0041] See Figure 3 , showed Figure 1 The diagram illustrates the structure of the variable inductance pole unit of an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor. The variable inductance pole unit comprises two identical variable inductance poles, with the symmetry center line of the two poles forming the direct axis of the unit. That is, the two identical variable inductance poles are symmetrically arranged on both sides of the direct axis of the unit. Each variable inductance pole includes N second permanent magnets radially arranged on the cross axis of the unit and second end magnetic barriers located at both ends of each second permanent magnet. The second end magnetic barriers extend to the outer ring of the asymmetric pole rotor, where N is an integer greater than or equal to 1. Preferably, N is 3. Specifically, the two identical variable inductance poles are designated as the first variable inductance pole and the second variable inductance pole, respectively.
[0042] like Figure 3As shown, the first variable inductance magnetic pole includes second permanent magnets 3-14, 3-15, and 3-16 arranged radially and in parallel on the rotor core. Second permanent magnet 3-14 is positioned near the outer ring of the rotor core, second permanent magnet 3-16 is positioned near the inner ring of the rotor core, and second permanent magnet 3-15 is positioned between second permanent magnets 3-14 and 3-16. Second end magnetic barriers 3-11 are provided at both ends of second permanent magnet 3-14, second end magnetic barriers 3-12 are provided at both ends of second permanent magnet 3-15, and second end magnetic barriers 3-13 are provided at both ends of second permanent magnet 3-16. The second end magnetic barriers 3-11, 3-12, and 3-13 extend to the outer ring of the asymmetric magnetic pole rotor. Preferably, the cross-sections of the second end magnetic barriers 3-11 and the second permanent magnet 3-14 form an isosceles trapezoidal shape with an open base. The cross-sections of the second end magnetic barrier 3-12 and the second permanent magnet 3-15 form an isosceles trapezoid with an open side of the long base. The cross-sections of the second end magnetic barrier 3-13 and the second permanent magnet 3-16 form an isosceles trapezoid with an open side of the long base. In this first variable inductance magnetic pole, the second permanent magnets 3-14, 3-15, and 3-16 are all cuboids, magnetized along their thickness direction, and the magnetization directions are the same. The structure of the second variable inductance magnetic pole is exactly the same as that of the first variable inductance magnetic pole, and the magnetization directions of the second permanent magnets are also the same (consistent).
[0043] It should be noted that the magnetization direction of the second permanent magnet in the variable inductor pole is the same as the magnetization direction of the first permanent magnet near the variable inductor pole. For example, see [link to example]. Figure 3 Since the first permanent magnet 3-6 is adjacent to the first variable inductor magnetic pole, the magnetization direction of the second permanent magnets 3-14, 3-15 and 3-16 is the same as that of the first permanent magnet 3-6.
[0044] The determination of whether the magnetization direction is the same or opposite is based on whether it points towards the air gap. If the magnetization direction of both permanent magnets points towards the air gap, they are considered to have the same magnetization direction. If the magnetization direction of one permanent magnet points towards the air gap and the magnetization direction of the other permanent magnet points towards the inner ring of the rotor core (the side away from the air gap), they are considered to have opposite magnetization directions.
[0045] In some embodiments of the present invention, the radial distance between the N second permanent magnets arranged radially on the cross axis of the variable inductance magnetic pole unit is the same, that is, the N second permanent magnets are placed in parallel with equal radial spacing.
[0046] In some embodiments of the present invention, when no current is applied, each variable flux pole has a first leakage magnetic path and a second leakage magnetic path. The first leakage magnetic path starts from the first permanent magnet away from the direct axis of the variable flux pole unit, passes sequentially through the first leakage magnetic bridge, the first permanent magnet close to the direct axis, and the second leakage magnetic bridge, and finally returns to the first permanent magnet away from the direct axis to form a closed loop; the second leakage magnetic path starts from the first permanent magnet away from the direct axis of the variable flux pole unit, passes sequentially through the first leakage magnetic bridge, the first permanent magnet close to the direct axis, and the radially inner side of the first leakage magnetic barrier, and finally returns to the first permanent magnet away from the direct axis to form a closed loop.
[0047] For example, see Figure 4 , showed Figure 1 The diagram illustrates the first and second leakage magnetic paths of the second variable flux pole in the variable flux pole unit of an asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor. The first leakage magnetic path flows from the first permanent magnet 3-9, through the first leakage magnetic bridge 3-20, the first permanent magnet 3-8, and the second leakage magnetic bridge 3-19, before returning to the first permanent magnet 3-9. The second leakage magnetic path flows from the first permanent magnet 3-9, through the first leakage magnetic bridge 3-20, the first permanent magnet 3-8, and the inner core of the first leakage magnetic barrier 3-5, before returning to the first permanent magnet 3-9. The leakage magnetic path of the first variable flux pole follows the same direction as that of the second variable flux pole.
[0048] In some embodiments of the present invention, the asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor has a first main flux path formed by each variable flux magnetic pole and a second main flux path formed by each variable inductance magnetic pole.
[0049] The first main magnetic flux path begins with the first permanent magnet close to the direct axis of the variable magnetic flux pole unit, passes through the first permanent magnet away from the direct axis, enters the stator structure through the air gap, and finally returns to the asymmetric magnetic pole rotor to form a closed loop.
[0050] The second main magnetic flux path begins at the second permanent magnet near the inner ring of the rotor core, passes radially through other second permanent magnets, enters the stator structure through the air gap, and finally returns to the asymmetric magnetic pole rotor along the symmetrical center line of the variable inductance magnetic pole unit to form a closed loop.
[0051] See Figure 5 , showed Figure 1 The first main flux path of the asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor is shown. Figure 5 The colored arrows in the diagram indicate the magnetic flux flow direction of the two first main magnetic flux paths. For example, the magnetic flux flow direction of one of the first main magnetic flux paths is as follows: starting from the first permanent magnet 3-8, passing through the first permanent magnet 3-9, air gap 2, stator teeth 1-3, stator yoke 1-1, stator teeth 1-3, air gap 2, and then returning to the first permanent magnet 3-8.
[0052] See Figure 6 , showed Figure 1 The second main flux path of the asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor is shown. Figure 6 The colored arrows in the diagram indicate the flux flow directions of the two second main flux paths. For example, one of the second main flux paths flows as follows: starting from the second permanent magnet 3-16, passing through the second permanent magnet 3-15, the second permanent magnet 3-14, air gap 2, stator teeth 1-3, stator yoke 1-1, stator teeth 1-3, air gap 2, and then returning to the second permanent magnet 3-16 along the symmetry center line of the variable inductance magnetic pole unit.
[0053] The asymmetric pole variable flux variable inductance reverse salient pole permanent magnet motor provided by this invention can change the saturation level of the first leakage flux bridge 3-17, the first leakage flux bridge 3-20, the second leakage flux bridge 3-18, and the second leakage flux bridge 3-19 by changing the magnitude of the armature current flowing through the stator windings 1-2. This, in turn, changes the magnitude of the leakage flux flowing through the first leakage flux bridge 3-17, the first leakage flux bridge 3-20, the second leakage flux bridge 3-18, and the second leakage flux bridge 3-19, thereby achieving dynamic adjustment of the main flux of the variable flux pole unit of the motor. This allows the controllable leakage flux to improve the field weakening capability of the motor at high speeds.
[0054] The electromagnetic field simulation software ANSYS Maxwell was used to simulate the embodiments of the present invention. Figure 1 The stator permanent magnet flux-switching permanent magnet motor shown was simulated. The asymmetric pole rotor 3 was set with an outer diameter of 208mm, an inner diameter of 89.6mm, an air gap of 0.8mm, a motor shaft length of 60mm, two variable flux pole units, and two variable inductance pole units. N=3, and the stator windings 1-2 had a rated armature current of 12A. c1 =l c2 =3mm, α pm1 =120°, simulation results are as follows Figure 7-10 As shown.
[0055] Figure 7 It shows Figure 1 The simulated no-load flux distribution waveform of the asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor is shown in the stator windings 1-2 under the condition that no current is applied. Based on... Figure 7 It can be seen that: (1) Each variable flux magnetic pole and each variable inductance magnetic pole corresponds to a main flux path, which passes through the air gap into the stator and returns to the rotor to form an effective loop; (2) Each variable flux magnetic pole has two leakage flux paths, which form a self-loop in the rotor variable flux magnetic pole and do not pass through the air gap to form an effective loop.
[0056] Figure 7The simulation results show that, under no-load conditions, a portion of the permanent magnet flux of the asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor provided by this invention closes inside the rotor via a leakage flux path, without passing through the air gap to form an effective loop. This leakage flux path enables the motor to achieve a low no-load back EMF design, laying the foundation for subsequent suppression of short-circuit current and improvement of safety.
[0057] Figure 8 It shows Figure 1 The simulated load flux distribution waveform of the asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor is shown when a rated current of 12A is applied to the stator windings 1-2. Based on... Figure 8 It can be seen that there is no leakage flux at any of the variable flux poles. This indicates that the leakage flux path is closed under load, the original leakage flux of each variable flux pole disappears, and is completely converted into effective flux, which passes through the air gap and enters the stator along the main magnetic path, thereby increasing the output torque of the motor.
[0058] Figure 8 The simulation results show that the asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor provided by this invention can adjust the air gap flux by controlling the saturation degree of the leakage magnetic bridge through the armature current. This means that during high-speed operation, the air gap flux can be automatically reduced and the rise of back electromotive force can be suppressed simply by controlling the current to change the saturation degree of the leakage magnetic bridge, without the need to inject negative direct-axis demagnetizing current.
[0059] Figure 9 It shows Figure 1 The curves shown represent the variations in permanent magnet air gap flux linkage, direct-axis inductance, and quadrature-axis inductance of an asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor as a function of the armature current flowing through the stator windings. Based on... Figure 9 It can be seen that when the armature current flowing through the stator winding increases, the permanent magnet air gap flux of the motor increases accordingly, and the motor maintains the reverse salient pole characteristic that the direct axis inductance is greater than the quadrature axis inductance.
[0060] Figure 10 It shows Figure 1 The figure shows the electromagnetic torque of an asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor as a function of the current angle of the armature current flowing through the stator winding. Based on... Figure 10 As can be seen, unlike traditional positive salient permanent magnet motors, the maximum electromagnetic torque of this motor is located at approximately -30° electrical angle. At this point, the direct-axis current is positive, and the motor outputs positive reluctance torque, effectively reducing the risk of irreversible demagnetization of the permanent magnet.
[0061] An asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to an embodiment of the present invention has at least one of the following advantages:
[0062] 1. This invention constructs a variable inductance magnetic pole unit by setting multiple layers of permanent magnets and magnetic barriers in the same layer. This unit has multiple layers of magnetic barriers on the quadrature-axis magnetic circuit to suppress quadrature-axis inductance, while the direct-axis magnetic circuit has no additional magnetic barriers or permanent magnets, thereby forming a direct-axis inductance greater than the quadrature-axis inductance (L). d >L q This paper describes a reverse salient pole motor structure. Based on this, a variable flux pole unit is introduced. By adjusting the permanent magnet air gap flux, the motor can achieve field weakening and speed increase at high speeds without injecting a negative direct-axis demagnetizing current, thus avoiding the output capacity reduction caused by the negative reluctance torque introduced by the demagnetizing current. Simultaneously, the variable inductance pole unit further increases the quadrature-axis reluctance through multiple layers of magnetic barriers, effectively suppressing the quadrature-axis inductance as the quadrature-axis current increases, and widening the difference between the direct and quadrature-axis inductance (L). d -L q This enhances the reluctance torque output capability at low speeds. The synergistic effect of the variable flux magnetic poles and the variable inductance magnetic poles enables the motor to operate efficiently across the entire speed range without relying on demagnetizing current, thus meeting the multi-condition requirements of low-speed high torque and high-speed wide speed range.
[0063] 2. During high-speed operation, the air gap flux of the permanent magnet is adjusted online by coordinating the double-layer leakage magnetic barrier (discontinuous sector-shaped magnetic barrier and first leakage magnetic barrier) in the variable flux magnetic pole with the figure-eight-shaped first permanent magnet, and by controlling the saturation degree of the leakage magnetic bridge using armature current. As the rotational speed increases, the air gap flux adaptively decreases with increasing speed, and the rise in back electromotive force is effectively suppressed. That is, the rotational speed can be increased without injecting demagnetizing current, which fundamentally reduces the risk of the permanent magnet being subjected to reverse magnetic field impact and significantly improves the permanent magnet's resistance to irreversible demagnetization.
[0064] 3. The three layers of magnetic barriers and embedded parallel permanent magnets in the variable inductance poles can dynamically adjust the quadrature and direct axis inductance parameters according to load changes, optimize the torque output capability under different working conditions, and work together with the variable flux poles to further broaden the constant power speed regulation range of the motor.
[0065] 4. In the present invention, the asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor, when unloaded or lightly loaded, a portion of the permanent magnet flux is directly closed inside the rotor through the leakage flux path, which reduces the effective magnetic flux passing through the air gap and correspondingly reduces the back EMF, thus exhibiting low no-load back EMF characteristics. It can significantly suppress short-circuit current without sacrificing overload capacity, further improving the safety and reliability of this type of motor.
[0066] While some embodiments of the present general inventive concept have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.
Claims
1. An asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor, comprising a stator structure and an asymmetric magnetic pole rotor, wherein the stator structure is sleeved on the outer periphery of the asymmetric magnetic pole rotor, and the asymmetric magnetic pole rotor comprises a rotor core and variable flux magnetic pole units and variable inductance magnetic pole units alternately arranged on the rotor core. The variable magnetic flux pole unit includes a magnetic barrier and two identical variable magnetic flux poles. The radial centerline of the magnetic barrier is the direct axis of the variable magnetic flux pole unit; the symmetrical centerline of the variable magnetic flux poles is the cross axis of the variable magnetic flux pole unit. The variable magnetic flux pole includes a first leakage magnetic barrier disposed on its symmetrical center line, two second leakage magnetic barriers symmetrically disposed on both sides of its symmetrical center line, and two first permanent magnets symmetrically disposed on both sides of its symmetrical center line in a figure-eight pattern with their opening sides facing the inner ring of the rotor core. The first permanent magnet has a first end magnetic barrier disposed at the first end near the inner ring of the rotor core. Two second leakage magnetic barriers form a discontinuous sector magnetic barrier, which is located between the first leakage magnetic barrier and the outer ring of the rotor core, with its outer end corresponding to the second end of the first permanent magnet. The variable inductance magnetic pole unit includes two identical variable inductance magnetic poles symmetrically arranged on both sides of its direct axis. The variable inductance magnetic pole includes N second permanent magnets arranged radially on the cross axis of the variable inductance magnetic pole unit and second end magnetic barriers disposed at both ends of each second permanent magnet. The second end magnetic barriers extend to the outer ring of the rotor core, and N is an integer greater than or equal to 1.
2. The asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to claim 1, characterized in that, The angle bisector of the direct axis of two adjacent variable flux magnetic pole units coincides with the direct axis of the variable inductance magnetic pole unit located between them.
3. The asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor according to claim 2, characterized in that, The quadrature axis of the variable flux magnetic pole unit and the direct axis of the variable inductance magnetic pole unit are both perpendicular to the stator winding at i d When a quadrature-axis current is applied under =0 control, the direction of the quadrature-axis magnetic field generated is consistent. The direct axis direction of the variable flux magnetic pole unit and the quadrature axis direction of the variable inductance magnetic pole unit are both consistent with the direction of the direct axis magnetic field generated when only a direct axis current is applied to the stator winding.
4. The asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to claim 1, characterized in that, Both the first permanent magnet and the second permanent magnet are cuboids and are magnetized along the thickness direction. In the variable magnetic flux pole unit, the two first permanent magnets near the magnetic barrier are magnetized in the same direction, while the first permanent magnets in the same variable magnetic flux pole are magnetized in opposite directions. The second permanent magnet is magnetized in the same direction and in the same direction as the first permanent magnet near the variable inductance pole.
5. The asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to claim 1, characterized in that, The first permanent magnets on both sides of the magnetic barrier are arranged in a V-shape with an included angle of α. pm1 Satisfying 90° < α pm1 <150°.
6. The asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to claim 1, characterized in that, The cross-section of the magnetic barrier is oblong, and its radial centerline coincides with the direct axis of the variable magnetic flux pole unit.
7. The asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to claim 1, characterized in that, N second permanent magnets are placed in parallel with equal radial spacing.
8. The asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to claim 1, characterized in that, When no armature current is applied, the variable magnetic flux pole has a first leakage magnetic path and a second leakage magnetic path. The first leakage magnetic path begins at the first permanent magnet far from the direct axis of the variable magnetic flux pole unit, passes sequentially through the first leakage magnetic bridge, the first permanent magnet close to the direct axis, and the second leakage magnetic bridge, and finally returns to the first permanent magnet far from the direct axis to form a closed loop; The second leakage magnetic path starts from the first permanent magnet away from the direct axis of the variable magnetic flux pole unit, passes through the first leakage magnetic bridge, the first permanent magnet close to the direct axis and the radially inner iron core of the first leakage magnetic barrier in sequence, and finally returns to the first permanent magnet away from the direct axis to form a closed loop. Among them, the first leakage magnetic bridge is located between the radial outer side of the discontinuous sector magnetic barrier and the outer ring of the rotor core; The second leakage magnetic bridge is located between the radial inner side of the discontinuous sector magnetic barrier and the radial outer side of the first leakage magnetic barrier.
9. The asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor according to claim 8, characterized in that, The first leakage magnetic bridge and the second leakage magnetic bridge have the same radial width.
10. The asymmetric pole-changing flux-changing inductance reverse salient pole permanent magnet motor according to claim 1, characterized in that, The asymmetric magnetic pole variable flux variable inductance reverse salient pole permanent magnet motor has a first main flux path and a second main flux path. The first main magnetic flux path begins with the first permanent magnet close to the direct axis of the variable magnetic flux pole unit, passes through the first permanent magnet away from the direct axis, enters the stator structure through the air gap, and finally returns to the asymmetric magnetic pole rotor to form a closed loop. The second main magnetic flux path begins at the second permanent magnet near the inner ring of the rotor core, passes radially through other second permanent magnets, enters the stator structure through the air gap, and finally returns to the asymmetric magnetic pole rotor to form a closed loop.