Low-inertia permanent magnet motor with high dynamic response

Abstract

The invention discloses a low-inertia permanent magnet motor with high dynamic response. According to the invention, the magnetostrictive layer is arranged at the magnetic bridge position of the rotor, micro-deformation is generated by using rapid change of current, local air gap spacing is transiently changed, local air gap magnetic resistance is changed, magnetic linkage amplitude limiting is realized, a reaction magnetoelastic moment with the same phase as the current change rate is superposed in an electromagnetic energy and mechanical energy conversion link, and the current change rate is changed. The magnetic flux linkage slope is softened, the sharp components of the high-frequency current and the magnetic field are effectively weakened, the overhigh rotating speed of the rotor is buffered, the overshoot and oscillation of the torque are directly weakened, the speed drop and backswing of the motor are remarkably reduced when the load suddenly changes, meanwhile, the peak current and the transient thermal shock are also inhibited, and as the magnetic flux linkage slope is softened, the sharp components of the high-frequency current and the magnetic field are effectively weakened. Therefore, electromagnetic noise and mechanical resonance excitation are reduced, and the motor is further ensured to have higher dynamic stability, control bandwidth and operation reliability while keeping the advantages of low inertia and quick response.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet motor technology, and more particularly to a low-inertia permanent magnet motor with high dynamic response. Background Technology

[0002] As the name suggests, low-inertia permanent magnet motors have rotors with intentionally designed rotational inertia at extremely low levels. This is typically achieved through optimized rotor geometry, the use of lightweight, high-strength materials, and sophisticated magnetic circuit design, aiming to minimize the driving torque required for rotor acceleration or deceleration. This design strategy significantly improves the motor's acceleration, deceleration, and dynamic response frequency, enabling the motor to precisely track control commands with extremely high bandwidth, achieving millisecond-level response speeds. This rapid response characteristic is crucial for applications requiring frequent starts and stops, rapid reversals, or high-precision trajectory tracking. For example, in collaborative robot joints, low-inertia motors give robotic arms more sensitive movements and faster reaction speeds, thereby improving production efficiency and the safety of human-robot interaction; in semiconductor manufacturing equipment, it ensures the ultra-high precision and repeatability of precision positioning systems, directly impacting product yield. Summary of the Invention

[0003] This invention overcomes the shortcomings of the prior art and provides a low-inertia permanent magnet motor with high dynamic response.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a high dynamic response, low inertia permanent magnet motor, comprising:

[0005] Stator; and

[0006] The rotor includes an iron core and a plurality of permanent magnets, the plurality of permanent magnets being arranged along the circumferential direction of the rotor inside the iron core, and the iron core forming a plurality of magnetic bridges between the permanent magnets;

[0007] The magnetic bridge has multiple pre-set grooves, and a magnetostrictive layer is embedded inside the grooves.

[0008] The magnetostrictive layer is made of a magnetostrictive material that undergoes reversible geometric deformation under a magnetic field, adjusting the local gap between the stator and the rotor.

[0009] In a preferred embodiment of the present invention, the magnetostrictive layer is composed of a plurality of independent magnetostrictive sheets, and the magnetostrictive sheets have a wavy cross-sectional structure along their length.

[0010] In a preferred embodiment of the present invention, a plurality of magnetostrictive sheets are stacked on top of each other, and adjacent magnetostrictive sheets are arranged in an alternating manner, such that the peak position of the upper magnetostrictive sheet corresponds to the trough position of the lower magnetostrictive sheet.

[0011] In a preferred embodiment of the present invention, a plurality of magnetostrictive sheets are arranged in an alternating manner to form a periodic contraction-expansion microchannel.

[0012] In a preferred embodiment of the present invention, the contraction-expansion microchannel includes alternating contraction sections and expansion sections; the through holes of the microchannel in the contraction section are arranged to gradually decrease, and the through holes of the microchannel in the expansion section are arranged to gradually increase.

[0013] In a preferred embodiment of the present invention, the magnetostrictive material of the magnetostrictive layer includes at least one of Terfenol-D, Galfenol, or Fe-Ga alloy.

[0014] In a preferred embodiment of the present invention, the magnetostrictive layer is fixed in the groove by means of bonding, pressing or welding.

[0015] In a preferred embodiment of the present invention, the iron core is composed of a plurality of iron chips stacked together, and each of the plurality of iron chips has a slot, and the slots of the plurality of iron chips stacked together form a groove.

[0016] In a preferred embodiment of the present invention, a frame is provided between the several stacked magnetostrictive sheets. The frame includes a rectangular frame. The rectangular frame is composed of several support strips arranged in an array between adjacent magnetostrictive sheets. The extension direction of the several support strips is the same as the channel direction of the contraction-expansion microchannel.

[0017] In a preferred embodiment of the present invention, the magnetostrictive layer that contacts the inner wall of the groove is fixed to the inner wall of the groove by bolts.

[0018] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0019] (1) This invention provides a low-inertia permanent magnet motor with high dynamic response. By setting a magnetostrictive layer at the magnetic bridge position of the rotor, the micro-deformation caused by rapid current change is used to transiently change the local air gap spacing and change the local air gap magnetic resistance, thereby limiting the magnetic flux. Then, a reaction magnetic elastic torque in phase with the current change rate is superimposed in the electromagnetic energy-mechanical energy conversion link, which plays a buffering role on the excessively high speed of the rotor, directly weakening the torque overshoot and oscillation. This significantly reduces the speed drop and sway of the motor when the load changes suddenly. At the same time, the peak current and transient thermal shock are also suppressed. Furthermore, since the magnetic flux slope is softened, the sharp components of high-frequency current and magnetic field are effectively weakened, thereby reducing electromagnetic noise and mechanical resonance excitation. This further ensures that the motor has higher dynamic stability, control bandwidth and operational reliability while maintaining the advantages of low inertia and fast response.

[0020] (2) The present invention provides a low-inertia permanent magnet motor with high dynamic response. The magnetostrictive layer is composed of several magnetostrictive sheets with wavy cross sections stacked together. The adjacent sheets are arranged alternately so that the peaks of the upper layer correspond to the troughs of the lower layer. By using the staggered arrangement, complementary undulating channels are formed in the structure, so that the magnetic flux is uniformly divided and a spatial phase difference is generated when passing through the magnetic bridge area, thereby weakening the high-order spatial harmonics and reducing the torque ripple. At the same time, the staggered arrangement of the stacked sheets can disperse the concentrated strain generated by the single sheet during the magnetostriction process, so that the magnetoresistive modulation process changes from abrupt to gradual, and the action of the reaction magnetoelastic torque is smoother, avoiding the harsh braking effect of the motor under rapid response.

[0021] (3) The present invention provides a low-inertia permanent magnet motor with high dynamic response. By using staggered and stacked corrugated sheets to form alternating contraction and expansion sections between the layers, a contraction-expansion circulating microchannel is formed. This allows the air gap magnetic flux to be periodically cut and re-converged when flowing through the rotor magnetic bridge region, forming a magnetoresistive modulation unit similar to the Venturi effect. This weakens higher-order spatial harmonics, reduces cogging torque and torque ripple from an electromagnetic perspective. At the same time, under the action of high-speed rotor rotation and centrifugal force, this periodic channel can generate microscale pressure difference drive for the air filled between the layers, promote internal heat flow circulation, accelerate the heat output in the contraction section, and achieve uniform diffusion in the expansion section, thereby significantly improving local hot spots and temperature rise distribution.

[0022] (4) This invention provides a low-inertia permanent magnet motor with high dynamic response. Through the wave-shaped structure and the interleaved magnetostrictive layer, the large-area conductive loop is broken. The intensity of the eddy current is inversely proportional to the area and resistance of the conductor loop. The wave-shaped and interleaved structure effectively reduces the circulation path and increases the equivalent resistance, thereby significantly weakening the eddy current in the high-frequency alternating magnetic field. This reduces the eddy current loss of the magnetostrictive layer under high dynamic operation and high-speed weak magnetic conditions, and lowers the temperature rise. This not only improves the overall efficiency of the motor, but also reduces high-frequency electromagnetic noise, enabling the motor to have higher energy efficiency and lower acoustic interference when running at high speed. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a perspective structural diagram of a preferred embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the internal structure of the motor in a preferred embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the rotor and stator structure of a preferred embodiment of the present invention;

[0027] Figure 4 This is a front view schematic diagram of the rotor and stator structure assembly according to a preferred embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the rotor structure of a preferred embodiment of the present invention;

[0029] Figure 6 This is a partial structural diagram of the magnetostrictive layer according to a preferred embodiment of the present invention;

[0030] In the diagram: 1. Stator; 2. Rotor; 3. Iron core; 4. Permanent magnet; 5. Magnetic bridge; 6. Groove; 7. Magnetostrictive layer; 8. Magnetostrictive sheet; 9. Support bar. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0035] Application Overview:

[0036] The low-inertia permanent magnet motor achieves its core design advantage at the cost of sacrificing sufficient "inertial buffering" or mechanical damping under dynamic disturbances. Specifically, when external load changes, shocks, or other disturbances occur, or when internal control commands experience current jumps such as rapid speed or position changes, the rotor's extremely low inertia means the system lacks sufficient mechanical rigidity or damping to smooth the acceleration shock caused by the transient and drastic changes in electromagnetic torque. This inherent underdamped characteristic in the physical mechanism makes the system highly susceptible to overshoot in the electromagnetic-to-mechanical energy conversion process, especially when rapid energy input or output occurs. This means the motor speed or position exceeds the target value before falling back down.

[0037] It was found that by introducing an adaptive mechanism with transient variable reluctance characteristics into the magnetic bridge 5 region of rotor 2, a current step is generated by the control command inside the permanent magnet motor. Through the deformation of the magnetostrictive material, the distance of the air gap between rotor 2 and stator 1 is locally reduced, thereby constructing a damping component for the rotation of rotor 2. This significantly suppresses overshoot, oscillation and potential instability problems caused by insufficient inertia in the motor under high-speed variable operating conditions or disturbed conditions.

[0038] like Figure 1 and Figure 2 As shown, a low-inertia permanent magnet motor with high dynamic response includes:

[0039] Stator 1; and

[0040] Rotor 2 includes an iron core 3 and multiple permanent magnets 4. The multiple permanent magnets 4 are arranged along the circumference of the rotor 2 inside the iron core 3, and the iron core 3 forms multiple magnetic bridges 5 between the permanent magnets 4, such as... Figure 3 and Figure 4 As shown;

[0041] Among them, the magnetic bridge 5 has multiple preset grooves 6, and a magnetostrictive layer 7 is embedded inside the grooves 6;

[0042] The magnetostrictive layer 7 is made of magnetostrictive material, which produces reversible geometric deformation under a magnetic field to adjust the local gap between the stator 1 and the rotor 2.

[0043] like Figure 5 As shown, a groove 6 is opened at the position of the magnetic bridge 5 of the rotor 2, and a magnetostrictive layer 7 is embedded inside the groove 6. The reason for choosing to arrange the structure in the magnetic bridge 5 area is that this position is itself a key magnetic flux path between the iron core 3 of the rotor 2 and the permanent magnet 4, which is the core link for controlling local magnetic resistance and affecting the speed of air gap magnetic flux establishment.

[0044] In the traditional rotor 2 structure, the magnetic bridge 5 serves as a compromise between mechanical support and magnetic flux path. Its size and shape mainly serve strength and leakage flux control. However, under the high-speed dynamic conditions of low-inertia motors, the response inertia of the magnetic bridge 5 region is insufficient, which often leads to the magnetic flux building up too quickly and directly triggers motor torque overshoot. Therefore, a magnetostrictive layer 7 is introduced in this region, which is equivalent to placing a dynamic buffer inside the motor that is triggered by the rate of change of current, thereby compensating for the deficiencies of the low-inertia structure.

[0045] Magnetostrictive materials are introduced into the motor, making it a physical feedback unit that automatically responds to changes in the rate of change of current.

[0046] Specifically, the magnetostrictive layer 7 is made of a material with a high magnetostriction coefficient, such as Terfenol-D or Fe-Ga alloy, and is installed in the groove 6 of the magnetic bridge 5. When the current in the stator 1 winding rises rapidly, the local magnetic field strength increases sharply, and the magnetostrictive material undergoes reversible geometric deformation on a microsecond timescale due to the magnetostrictive effect.

[0047] This deformation alters the local air gap reluctance, limiting the speed at which the air gap flux linkage is established. Instead of approaching the step curve of the current infinitely, it exhibits a limiting and hysteresis effect, thus flattening the torque growth process and giving the output characteristics the effect of virtual inertia.

[0048] It should be noted that this virtual inertia is triggered when the rate of change of current is large, which is equivalent to a nonlinear, transient dynamic damping mechanism. Unlike the traditional physical inertia, this response mechanism does not require adding actual mass to rotor 2, nor does it require sacrificing acceleration and deceleration performance. Instead, it directly suppresses torque overshoot through dynamic adjustment of reluctance.

[0049] For example, when a joint encounters a sudden braking command during high-speed movement, a traditional low-inertia motor will swing in the opposite direction due to excessively fast response, causing the end of the robotic arm to vibrate. The virtual inertia structure of this invention can absorb some energy at this moment and suppress the torque peak, thereby stabilizing the joint in the target position in the shortest possible time.

[0050] Among them, the virtual inertia can be regarded as the reaction magnetoelastic torque in phase with the rate of change of current. When the current rises rapidly in the positive direction, the magnetostrictive layer 7 extends outward due to the enhanced magnetic field, which increases the local air gap magnetic resistance and restricts the growth of the magnetic flux, which is equivalent to adding braking to the process of torque rise.

[0051] When the current drops rapidly, the magnetostrictive layer 7 contracts as the magnetic field weakens, releasing the energy stored in the local magnetic flux, which is equivalent to dragging the torque during the decrease process.

[0052] This two-way interaction creates an equivalent inertia effect, making the system's dynamic performance more stable. It is worth noting that this process leaves no residue after the external disturbance disappears, the magnetostrictive layer 7 is fully reset, and the motor still maintains its fast response advantage with low inertia. This is different from traditional mechanical damping, which often leads to continuous energy loss and hysteresis.

[0053] Specifically, the core innovation of the permanent magnet motor disclosed in this invention lies in the structural optimization of the magnetic bridge 5 region of its rotor 2. At least one magnetostrictive layer 7 is embedded or integrated into the magnetic bridge 5 slot inside the iron core of the rotor 2.

[0054] The magnetostrictive layer 7 is refined from specific functional materials that have a significant magnetostrictive effect. Typical materials include, but are not limited to, iron-based rare earth alloys such as Fe-Ga alloys, trade name Galfenol; or TbDyFe alloys, trade name Terfenol-D, as well as certain nickel-based or cobalt-based magnetostrictive materials.

[0055] The selection of such materials is based on their excellent saturation magnetostriction coefficient under high magnetic field strength, low hysteresis loss, and moderate Curie temperature to ensure the stability of their performance within the actual operating temperature range of the motor.

[0056] For example, for Fe-Ga alloys, the saturation magnetostriction coefficient can reach about 300-400 ppm, the Curie temperature is usually above 300℃, and the Young's modulus is about 50-100 GPa, which together determine its ability to produce controllable micron-level deformation under the action of a magnetic field.

[0057] The magnetostrictive layer 7 is installed in the groove 6, which is arranged on the main magnetic flux path of the rotor 2 magnetic bridge 5. It is usually located in the magnetic reluctance path between the permanent magnet 4 and the air gap, or between adjacent magnetic poles, to ensure that the magnetostrictive component can directly and efficiently sense the transient magnetic field strength change caused by the change of motor winding current.

[0058] When the current in the motor windings undergoes rapid changes, i.e., when it is in a high current change rate condition, such as during rapid start-up, emergency braking, or sudden load changes, the resulting transient alternating magnetic field will excite the magnetostrictive component to rapidly produce directional and reversible geometric deformation.

[0059] This deformation is typically in the micrometer range; for example, for a magnetostrictive component with a length of 10 millimeters, the length change may be between several micrometers and tens of micrometers.

[0060] Considering that the response of a single monolithic magnetostrictive layer 7 is too concentrated when triggered by a current step, resulting in abrupt changes in local magnetoresistance and pulse characteristics of the reaction magnetic torque, although it can suppress overshoot, it may also introduce secondary oscillations; moreover, thick bulk magnetostrictive materials are prone to stress concentration and fatigue cracks under long-term high-frequency stretching and contraction, resulting in insufficient structural stability.

[0061] Specifically, by setting a magnetostrictive layer at the magnetic bridge position of the rotor, the rapid change of current causes micro-deformation, transiently changing the local air gap spacing and altering the local air gap magnetic reluctance, thus limiting the magnetic flux. This results in a superimposed reaction magnetoelastic torque in phase with the rate of change of current in the electromagnetic-mechanical energy conversion link, which buffers the excessively high rotor speed, directly reducing torque overshoot and oscillation. This significantly reduces speed drop and sway when the motor experiences sudden load changes, while also suppressing peak current and transient thermal shock. Furthermore, because the magnetic flux slope is softened, the sharp components of high-frequency current and magnetic field are effectively weakened, thereby reducing electromagnetic noise and mechanical resonance excitation. This further ensures that the motor maintains its advantages of low inertia and fast response while possessing higher dynamic stability, control bandwidth, and operational reliability.

[0062] Therefore, this embodiment proposes a stacking and staggered arrangement scheme for a wavy cross-section magnetostrictive sheet 8. In this embodiment, the magnetostrictive layer 7 is refined into several independent sheets with wavy cross-sections, and the upper and lower layers are staggered so that the peaks of the upper layer correspond to the troughs of the lower layer, forming a spatial complementary structure.

[0063] like Figure 6 As shown, the staggered design of the wavy laminated sheets geometrically increases the flexible response space of the magnetostrictive layer 7.

[0064] By utilizing the fact that the corrugated cross section is different from the structure of a flat sheet, when the magnetostrictive material expands and contracts under the action of a magnetic field, the crest part deforms preferentially because it is close to the air gap, while the trough part is relatively lagging behind because it is embedded deeper into the rotor 2.

[0065] The staggered arrangement between the upper and lower layers allows the overall response process to be artificially dispersed in different phases, achieving time-division and zone-division magnetoresistive modulation. The dispersion effect makes the formation process of virtual inertia smoother, and the reaction magnetic torque no longer superimposes in a sudden manner, but accumulates layer by layer, thus avoiding the occurrence of secondary oscillations.

[0066] Meanwhile, the interlaced wave plates are equivalent to constructing multiple miniature magnetoresistive modulation units in different spatial positions. When the current in stator 1 rises sharply, the upper wave plate near the air gap deforms first, restricting the establishment of some magnetic flux.

[0067] The lower trough plate begins to respond under hysteresis, further adjusting the magnetic reluctance. This process is similar to a multi-stage limiter, causing the flux linkage response curve to change from a step to a ramp. This not only improves the linearity of the virtual inertia but also enables the system to achieve effective suppression under different frequency conditions, thereby expanding the dynamic stability operating range of the motor.

[0068] It should be noted that the wave-shaped and staggered arrangement also indirectly creates multi-dimensional heat dissipation channels. Due to the misalignment of the peaks and troughs, a large number of irregular gaps are formed between the layers. Under the action of the high-speed rotation of rotor 2 and centrifugal force, these channels can guide air or fill thermal conductive adhesive to form micro-circulation, thereby enhancing local heat dissipation performance.

[0069] The wave-shaped interlaced structure of this embodiment significantly improves the smoothness of virtual inertia, making the torque response of the motor under current step triggering smoother and avoiding additional secondary oscillations. At the same time, the structure brings dual optimization of electromagnetics and heat: on the one hand, high-frequency harmonics are weakened by multi-level magnetoresistive modulation, reducing torque ripple; on the other hand, heat dissipation is enhanced by interlayer paths, ensuring the stability and reliability of the motor in long-term operation.

[0070] In this invention, several magnetostrictive sheets 8 are arranged in an alternating manner to form a periodic contraction-expansion microchannel.

[0071] The contraction-expansion microchannel consists of alternating contraction and expansion sections; the through-holes of the microchannel in the contraction section are arranged to gradually decrease in size, while the through-holes of the microchannel in the expansion section are arranged to gradually increase in size.

[0072] By arranging several magnetostrictive plates 8 in an alternating pattern of upper and lower peaks and valleys, a contraction-expansion microchannel that repeats periodically in the direction of the polar arc is naturally formed between the layers. The contraction section is equivalent to the rapid rise region of the local air gap magnetic reluctance, and the expansion section is equivalent to the fall region of the local magnetic reluctance. When the main magnetic flux crosses the magnetic bridge 5, it is divided into multiple paths with spatial phase differences by this set of periodic units, thereby interfering and weakening the higher-order spatial harmonics of the air gap magnetic field, thereby reducing torque ripple and radial electromagnetic force fluctuations.

[0073] Because the contraction section is closer to the air gap and more sensitive to changes in the magnetic field, it produces magnetostrictive micro-deformation and increases local magnetic resistance; the subsequent expansion section, due to its inward position and difference in mechanical compliance, responds with a lag, thus forming a stepped amplitude limiting curve that first suppresses and then slows down within one cycle.

[0074] Furthermore, when there is a current step or external disturbance, the equivalent reaction magnetoelastic torque is no longer injected in the form of pulses, but rises continuously and reaches its peak value after multiple cycles are superimposed, thereby reducing the overshoot peak value and shortening the settling time.

[0075] By utilizing the contraction-expansion geometry, a predictable microscale pressure difference is generated between the layers under the rotation of rotor 2 and centrifugal force. The air or heat-conducting medium in the channel forms a local micro-circulation that accelerates from contraction to expansion. Under the high-speed rotation of rotor 2 and the action of centrifugal force, a microscale pressure difference can be generated to drive the air filled between the layers, promote the internal heat flow circulation, accelerate the heat out of the contraction section, and achieve uniform diffusion in the expansion section, thereby significantly improving the local hot spots and temperature rise distribution.

[0076] It should be noted that the staggered stacking and periodic channels together cut the potential eddy current loop into several sub-loops with smaller scale and longer paths. The contraction-expansion wall undulations increase the equivalent resistance and magnetic reluctance, suppress the circulation current and local saturation under the high-frequency alternating magnetic field, and break the large-area conductive loop. By utilizing the inverse relationship between the intensity of the eddy current and the area and resistance of the conductor loop, the wavy and staggered structure effectively reduces the circulation path and increases the equivalent resistance, thereby significantly weakening the eddy current in the high-frequency alternating magnetic field. This reduces the eddy current loss and temperature rise of the magnetostrictive layer 7 under high dynamic operation and high-speed weak magnetic conditions, which not only improves the overall efficiency of the motor, but also reduces high-frequency electromagnetic noise, enabling the motor to have higher energy efficiency and lower acoustic interference when running at high speed.

[0077] In this invention, the magnetostrictive layer 7 is fixed in the groove by bonding, pressing or welding.

[0078] The iron core 3 is composed of several iron chips stacked together, and each iron chip has a slot. The slots of the stacked iron chips form a groove 6.

[0079] A frame is provided between several stacked magnetostrictive sheets 8. The frame includes a rectangular frame. The rectangular frame is composed of several support bars 9 arranged in an array between adjacent magnetostrictive sheets 8. The extension direction of the support bars 9 is the same as the channel direction of the contraction-expansion microchannel.

[0080] The magnetostrictive layer 7, which is in contact with the inner wall of the groove 6, is fixed to the inner wall of the groove 6 by bolts.

[0081] The present invention employs a composite fixing mechanism of adhesive bonding and mechanical pre-tightening to fix the magnetostrictive layer 7. Specifically, the layer of the magnetostrictive sheet 8 that contacts the inner wall of the groove is fixed with a high-temperature fatigue-resistant adhesive so that it can be reliably embedded in the groove 6; on the outside of the adhesive layer, a metal pressure plate and bolts are used for pre-tightening so that the whole is sufficiently constrained in both the axial and radial directions.

[0082] This dual fixation ensures that the magnetostrictive layer 7 can withstand high-frequency stress and avoid failure due to adhesive aging, effectively preventing peeling problems caused by long-term thermal cycling.

[0083] In order to maintain the gap between the layers, this embodiment introduces a support structure between the stacked magnetostrictive sheets 8;

[0084] The specific structure includes a rectangular frame and several support strips 9 extending in the same direction as the microchannel. The support strips 9 form a uniform mechanical separation between the layers. The rigid part prevents the layers from radially shifting under centrifugal force, while the flexible part allows for small displacement under magnetostrictive strain. This ensures that the geometric gap does not collapse and does not inhibit the stretching effect of the magnetostrictive material itself, so that the microchannel morphology can be maintained stably for a long time and the electromagnetic and thermal effects will not be attenuated due to structural relaxation.

[0085] This ensures that when a step current is applied to the motor, the magnetostrictive sheet 8 still undergoes slight deformation in the designed direction, and the local air gap magnetic resistance is modulated accordingly, thereby generating virtual inertia and harmonic attenuation effects. During this process, the microchannels between the layers are constrained by the support frame and will not collapse or become blocked, thus maintaining the heat dissipation cycle.

[0086] When the present invention is used, after the stator 1 is energized, a rotating magnetic field is established in the air gap. The permanent magnet 4 of the rotor 2 is subjected to the magnetic field to generate electromagnetic torque and drive the motor to rotate. When the motor is in normal steady-state operation, the magnetostrictive layer 7 in the slot of the magnetic bridge 5 of the rotor 2 is in an undeformed state. The magnetic reluctance path is similar to that of a traditional motor and will not inhibit the fast response characteristics of the low inertia motor.

[0087] When the motor receives a current step signal from an external controller, or when the stator 1 current changes rapidly due to load disturbance, the magnetostrictive layer 7 undergoes a small reversible deformation under the enhanced local magnetic field, thereby instantaneously changing the local air gap magnetic reluctance of the magnetic bridge 5. The magnetic flux establishment process is limited and delayed, which is equivalent to superimposing a reaction magnetoelastic torque that is in phase with the rate of change of current in the conversion link between electromagnetic energy and mechanical energy. This makes the rise of the motor output torque no longer exhibit overshoot, but forms a gradual rise process, which is equivalent to introducing a virtual inertia buffer effect in a low inertia system.

[0088] When the magnetostrictive layer 7 is composed of several magnetostrictive sheets 8 with wavy cross sections stacked together and arranged in an alternating manner to form a periodic contraction-expansion microchannel, the geometric shape of the alternating peaks and troughs causes the magnetic flux to be periodically cut and merged when crossing the magnetic bridge 5, forming a distributed magnetoresistive modulation unit. This weakens the harmonics caused by the cogging effect and significantly reduces torque ripple. At the same time, the microchannel generates a centrifugal driving effect when the rotor 2 rotates at high speed, causing the interlayer air or thermal conductive adhesive to circulate between the contraction and expansion sections, actively carrying away the local heat in the magnetic bridge 5 area and reducing the temperature rise of hot spots.

[0089] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A low-inertia permanent magnet motor with high dynamic response, characterized in that, include: stator; as well as The rotor includes an iron core and a plurality of permanent magnets, the plurality of permanent magnets being arranged along the circumferential direction of the rotor inside the iron core, and the iron core forming a plurality of magnetic bridges between the permanent magnets; The magnetic bridge has multiple pre-set grooves, and a magnetostrictive layer is embedded inside the grooves. The magnetostrictive layer is made of a magnetostrictive material that undergoes reversible geometric deformation under a magnetic field, adjusting the local gap between the stator and the rotor.

2. The high dynamic response, low inertia permanent magnet motor according to claim 1, characterized in that: The magnetostrictive layer is composed of several independent magnetostrictive sheets, each of which has a wavy cross-sectional structure along its length.

3. The high dynamic response, low inertia permanent magnet motor according to claim 1, characterized in that: Several magnetostrictive sheets are stacked on top of each other, and adjacent magnetostrictive sheets are arranged in an alternating manner, such that the peak position of the upper magnetostrictive sheet corresponds to the trough position of the lower magnetostrictive sheet.

4. A high dynamic response, low inertia permanent magnet motor according to claim 2, characterized in that: The magnetostrictive sheets are arranged in an alternating manner to form a periodic contraction-expansion microchannel.

5. A high dynamic response, low inertia permanent magnet motor according to claim 4, characterized in that: The contraction-expansion microchannel includes alternating contraction and expansion sections; the through holes of the microchannel in the contraction section are arranged to gradually decrease in size, and the through holes of the microchannel in the expansion section are arranged to gradually increase in size.

6. A high dynamic response, low inertia permanent magnet motor according to claim 1, characterized in that: The magnetostrictive material of the magnetostrictive layer includes at least one of Terfenol-D, Galfenol, or Fe-Ga alloy.

7. A high dynamic response, low inertia permanent magnet motor according to claim 1, characterized in that: The magnetostrictive layer is fixed in the groove by bonding, pressing, or welding.

8. A high dynamic response, low inertia permanent magnet motor according to claim 1, characterized in that: The iron core is composed of a number of stacked iron chips, and each of the iron chips has a slot, and the slots of the stacked iron chips form a groove.

9. A high dynamic response, low inertia permanent magnet motor according to claim 4, characterized in that: A frame is provided between several stacked magnetostrictive sheets. The frame includes a rectangular frame. The rectangular frame is composed of several support bars arranged in an array between adjacent magnetostrictive sheets. The extension direction of the support bars is the same as the channel direction of the contraction-expansion microchannel.

10. A high dynamic response, low inertia permanent magnet motor according to claim 1, characterized in that: The magnetostrictive layer that contacts the inner wall of the groove is fixed to the inner wall of the groove by bolts.

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