High-overload-capacity consequent-pole bidirectional modulation permanent magnet motor

Abstract

The invention discloses a consequent-pole bidirectional magnetic field modulation permanent magnet motor with high overload capacity. The permanent magnet motor comprises a stator (1), a rotor (2) and a motor rotating shaft (3), wherein the stator (1) comprises a stator yoke part (1.1), stator teeth (1.2), an armature winding (1.3) and tangential magnetizing magnetic steel (1.4), the rotor (2) comprises a rotor iron core (2.1), radial magnetizing magnetic steel (2.2) and rotor teeth (2.3), and the rotor (2) is fixed on the periphery of the rotating shaft (3) to be connected into a whole; and an air gap exists between the stator (1) and the rotor (2). The armature winding adopts a concentrated winding; the rotor comprises a rotor iron core and radial magnetizing magnetic steel; through the design of the consequent poles of the rotor, the permanent magnet consumption and the manufacturing cost are remarkably reduced; meanwhile, the torque density and the overload capacity of the motor are effectively improved by utilizing the modulation effect of the bidirectional magnetic field and the variable leakage flux effect of the stator permanent magnet.

Description

Technical Field

[0001] This invention relates to a high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor, belonging to the field of low-speed, high-torque permanent magnet motors. Background Technology

[0002] In the fields of high-end equipment and intelligent manufacturing, applications such as robot joints, heavy machine tools, and electric ship propulsion systems place stringent requirements on drive systems, demanding low speed, high torque, and high dynamic response. Traditional solutions employ a "rotary motor + gearbox" configuration, which leads to problems such as system efficiency loss, structural complexity, backlash, and the need for regular maintenance. Therefore, low-speed, high-torque permanent magnet direct-drive motors capable of directly driving loads have become the ideal technological choice.

[0003] To achieve the high torque density required for direct drive, permanent magnet motors based on the principle of magnetic field modulation have attracted widespread attention. These motors achieve an "electromagnetic deceleration" effect by modulating the magnetic field through the stator and rotor teeth, thus obtaining torque output capabilities far exceeding those of traditional motors without increasing mechanical complexity. However, existing magnetic field modulation motors still face two major contradictions: first, the extensive use of high-performance rare-earth permanent magnets in pursuit of high torque leads to high material costs; second, magnetic field modulation often relies on single-sided permanent magnet excitation, resulting in limited modulation depth. Under overload conditions, torque increase is easily constrained by the risk of permanent magnet demagnetization, and significant torque ripple exists. While existing alternating pole motors have reduced manufacturing costs to some extent, this single-sided alternating pole structure has inherent limitations in modulation depth, harmonic utilization, and torque stability. In particular, how to achieve higher output torque, stronger overload capacity, and lower torque ripple while utilizing alternating poles to reduce costs remains a critical technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0004] Purpose of the invention: This invention aims to overcome the shortcomings of existing low-speed, high-torque permanent magnet motors, such as high cost and insufficient overload capacity, and proposes a new type of permanent magnet motor based on alternating poles and bidirectional magnetic field modulation, to achieve low-cost, high-torque, and high-overload capacity low-speed, high-torque direct drive.

[0005] Technical solution: The present invention provides a high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor, which includes a stator, a rotor and a motor shaft; wherein, the stator is composed of a stator yoke, stator teeth, armature winding and tangential magnets, and the rotor is composed of a rotor core, radial magnets and rotor teeth, and the rotor is fixed on the outer periphery of the shaft and connected as a whole; there is an air gap between the stator and the rotor.

[0006] In the stator, the outermost periphery is the stator yoke, and stator teeth are provided on the inner periphery of the stator yoke. An armature winding is provided in the stator slot between every two stator teeth. Tangential magnets are provided on the inner side of the armature winding, i.e., at the slot opening of the stator slot. The magnetization directions of two adjacent tangential magnets are opposite.

[0007] In the rotor, the rotor core has a salient pole structure, and rotor teeth are provided on the outer periphery of the rotor core. Radial magnets are provided in the salient pole rotor slots between every two rotor teeth, and the magnetization direction of all radial magnets is radially outward from the axis of the rotating shaft.

[0008] The armature winding adopts a concentrated winding.

[0009] The rotor core has a salient pole structure.

[0010] The rotor teeth are trapezoidal teeth, which are alternately arranged with radially magnetized magnets to form an alternating pole structure for the rotor.

[0011] The rotor core is made of the same material as the stator core.

[0012] The stator includes 12 stator slots and 12 tangentially magnetized magnets.

[0013] The rotor comprises 17 radially magnetized magnets, which together with the rotor teeth form 17 pairs of poles.

[0014] The tangentially magnetized magnets can form a stator variable leakage flux effect. When the armature current is small, most of the stator magnet flux closes through the stator teeth and stator yoke, forming leakage flux. When the armature current increases, the armature magnetic field forces the magnetic flux generated by the stator magnets to pass through the air gap and close, becoming the main magnetic flux. The magnetic flux generated by the stator magnets is modulated by the rotor teeth, and the magnetic flux generated by the rotor magnets is modulated by the stator teeth. The stator and rotor work together to form a bidirectional magnetic field modulation effect, which enhances the types and amplitudes of working harmonics. Beneficial effects

[0015] (1) The rotor teeth and radial magnets of this motor are alternately arranged to form an alternating pole structure design, which reduces the amount of rare earth permanent magnet material used and reduces manufacturing costs; (2) The rotor magnetic field of this motor effectively compensates for the inherent defect of low torque in traditional slotted permanent magnet stator permanent magnet motors (hereinafter referred to as traditional stator permanent magnet motors) under light load. Under light load, traditional stator permanent magnet motors have a weak armature reaction magnetic field, making it difficult to fully utilize the permanent magnet magnetic field, resulting in a decrease in torque output capability. This design introduces alternating pole permanent magnets on the rotor side to provide an additional rotor permanent magnet magnetic field that is relatively independent of the load current. This magnetic field directly enhances the effective magnetic field of the air gap under light load, thereby compensating for the torque drop caused by insufficient armature magnetic field and ensuring the smoothness and sufficiency of torque output from light load to rated load range.

[0016] (3) This invention solves the problem of limited magnetic field enhancement capability of traditional vernier motors under deep saturation. Traditional alternating pole vernier motors tend to saturate their magnetic field under overload conditions and lack additional magnetic field adjustment methods, resulting in limited overload capability. This design introduces a stator leakage flux mechanism, effectively introducing leakage flux into the air gap working magnetic field under core saturation conditions, thereby dynamically enhancing the effective excitation on the rotor side. Therefore, this invention not only maintains higher output torque under overload conditions but also achieves overload capability and operational stability far exceeding that of traditional alternating pole vernier motors.

[0017] (4) The stator and rotor magnets of this motor are matched with special pole slots. The magnetic flux generated by the stator magnet is modulated by the rotor teeth, and the magnetic flux generated by the rotor magnet is modulated by the stator teeth. The stator and rotor work together to form a bidirectional magnetic field modulation effect, which increases the types and amplitudes of effective working harmonics, further improves the torque density, and significantly improves the overload capacity.

[0018] (5) Through structural design, this motor deeply integrates and mutually promotes the "stator variable leakage flux effect" and the "stator-rotor bidirectional magnetic field modulation effect," thereby achieving a synergistic performance improvement. On the one hand, the bidirectional magnetic field modulation effect significantly increases the number and amplitude of effective harmonics in the air gap magnetic field, laying the magnetic field foundation for high torque density; on the other hand, the stator variable leakage flux effect dynamically adjusts the distribution and utilization rate of permanent magnet flux when the load changes. Thus, it solves the contradiction between torque density and overload capacity that is difficult to balance in traditional single permanent magnet motors, achieving a significant synchronous improvement in both. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the structure of the motor of the present invention.

[0021] Figure 2 This is a schematic diagram illustrating the mechanism by which the overload capacity of the motor of the present invention is improved.

[0022] Figure 3 This is a transient torque waveform diagram of the motor of the present invention.

[0023] Figure 4 This is the torque-current characteristic curve of the motor of the present invention.

[0024] The diagram includes: stator 1, stator yoke 1.1, stator teeth 1.2, armature winding 1.3, tangential magnetized magnet 1.4, rotor 2, rotor core 2.1, radial magnetized magnet 2.2, rotor teeth 2.3, and shaft 3. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings in the embodiments of the present invention.

[0026] See Figure 1 The motor of the present invention includes a stator 1, a rotor 2, and a shaft 3; wherein, the stator 1 is composed of a stator yoke 1.1, stator teeth 1.2, armature winding 1.3, and tangential magnets 1.4, and the rotor 2 is composed of a rotor core 2.1, radial magnets 2.2, and rotor teeth 2.3, and the rotor 2 is fixed to the outer periphery of the shaft 3 and connected as a whole; there is an air gap between the stator 1 and the rotor 2.

[0027] In the stator 1, the outermost periphery is the stator yoke 1.1. Stator teeth 1.2 are provided on the inner periphery of the stator yoke 1.1. An armature winding 1.3 is provided in the stator slot between every two stator teeth 1.2. A tangentially magnetized magnet 1.4 is provided inside the armature winding 1.3, i.e., at the slot opening of the stator slot. The magnetization directions of adjacent tangentially magnetized magnets 1.4 are opposite. The armature winding 1.3 is a concentrated winding. The stator includes 12 stator slots and 12 tangentially magnetized magnets.

[0028] In the rotor 2, the rotor core 2.1 has a salient pole structure. The outer circumference of the rotor core 2.1 is provided with rotor teeth 2.3. Radial magnets 2.2 are provided in the salient pole rotor slots between every two rotor teeth 2.3. The magnetization direction of all radial magnets 2.2 is radially outward from the axis of the rotating shaft 3. The rotor core 2.1 has a salient pole structure. The rotor teeth 2.3 are trapezoidal teeth, alternately arranged with the radial magnets 2.2, forming an alternating pole structure for the rotor. The rotor includes 17 radial magnets 2.2, which, together with the rotor teeth 2.3, constitute 17 pairs of poles.

[0029] The rotor 2 core is made of the same material as the stator 1 core.

[0030] The tangentially magnetized magnet 1.4 can form a stator variable leakage flux effect; when the armature current is small, most of the stator magnet flux closes through the stator teeth and stator yoke, forming leakage flux; when the armature current increases, the armature magnetic field forces the magnetic flux generated by the stator magnet to pass through the air gap and close to become the main magnetic flux; the magnetic flux generated by the stator magnet is modulated by the rotor teeth, and the magnetic flux generated by the rotor magnet is modulated by the stator teeth. The stator and rotor cooperate to form a bidirectional magnetic field modulation effect, which enhances the types and amplitudes of working harmonics.

[0031] See Figure 2The permanent magnets in the stator slots can utilize the variable leakage flux effect. When the armature current is small, most of the stator magnet flux closes through the stator teeth and stator yoke, forming leakage flux. When the armature current increases, the armature magnetic field forces the flux generated by the stator magnets to close through the air gap and become the main flux. Therefore, it can compensate for the insufficient output capacity of a single rotor permanent magnet motor under overload conditions. Meanwhile, the rotor permanent magnets can improve the problem of low torque under light load when only the stator permanent magnets provide excitation. The two compensate for each other, achieving stronger overload capacity and higher torque density.

[0032] See Figure 3 The motor of this invention outputs excellent average torque under rated current, and the torque ripple is only 5%, which proves its high torque density and high running stability.

[0033] See Figure 4 Its average torque exhibits a unique, near-linear growth trend with increasing current until saturation, and it maintains strong output even at 150% of rated current, verifying its excellent overload capacity. This is attributed to the enhancement and effective utilization of harmonics by bidirectional magnetic field modulation, as well as the positive contribution of the variable leakage flux effect of the stator magnets during overload.

[0034] The above are merely preferred embodiments of the present invention. It should be understood that the number of stator slots, rotor teeth, and the background of the arc motor itself in these embodiments are merely examples of the present invention. The methods protected by the present invention should not be limited to the embodiments of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

Claims

1. A high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor, characterized in that, It includes a stator (1), a rotor (2) and a motor shaft (3); wherein the stator (1) is composed of a stator yoke (1.1), stator teeth (1.2), armature winding (1.3) and tangential magnets (1.4), and the rotor (2) is composed of a rotor core (2.1), radial magnets (2.2) and rotor teeth (2.3). The rotor (2) is fixed on the outer periphery of the shaft (3) and connected as a whole; there is an air gap between the stator (1) and the rotor (2).

2. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, In the stator (1), the outermost periphery is the stator yoke (1.1), and stator teeth (1.2) are provided on the inner periphery of the stator yoke (1.1). An armature winding (1.3) is provided in the stator slot between every two stator teeth (1.2). A tangential magnet (1.4) is provided on the inner side of the armature winding (1.3), i.e., at the slot opening of the stator slot. The magnetization directions of two adjacent tangential magnets (1.4) are opposite.

3. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, In the rotor (2), the rotor core (2.1) is a salient pole structure. The outer periphery of the rotor core (2.1) is provided with rotor teeth (2.3). Radial magnets (2.2) are provided in the salient pole rotor slots between every two rotor teeth (2.3). The magnetization direction of all radial magnets (2.2) is radially outward from the axis of the rotating shaft (3).

4. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, The armature winding (1.3) adopts a concentrated winding.

5. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, The rotor core (2.1) has a salient pole structure.

6. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, The rotor teeth (2.3) are trapezoidal teeth, which are alternately arranged with radially magnetized magnets (2.2) to form an alternating pole structure for the rotor.

7. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, The rotor (2) core is made of the same material as the stator (1) core.

8. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, The stator includes 12 stator slots and 12 tangentially magnetized magnets.

9. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, The rotor comprises 17 radially magnetized magnets (2.2), which together with the rotor teeth (2.3) form 17 pairs of poles.

10. The high overload capacity alternating pole bidirectional magnetic field modulation permanent magnet motor according to claim 1, characterized in that, The tangentially magnetized magnet (1.4) can form a stator variable leakage flux effect; when the armature current is small, most of the stator magnet flux closes through the stator teeth and stator yoke, forming leakage flux; when the armature current increases, the armature magnetic field forces the magnetic flux generated by the stator magnet to pass through the air gap and close to become the main magnetic flux; the magnetic flux generated by the stator magnet is modulated by the rotor teeth, and the magnetic flux generated by the rotor magnet is modulated by the stator teeth. The stator and rotor cooperate to form a bidirectional magnetic field modulation effect, which enhances the types and amplitudes of working harmonics.

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