Axial split-phase magnetically enhanced three-phase high-speed switched reluctance motor based on cogging magnetization

Abstract

This invention discloses an axially split-phase magnetically enhanced three-phase switched reluctance motor based on toothed slot insertion magnetization. By designing the stator and rotor tooth surface structure, the working air gap magnetic flux is increased when the stator teeth are aligned with the rotor teeth, and decreased when the stator teeth are aligned with the rotor slots, thus increasing the effective magnetic flux and thereby improving the electromagnetic torque. This invention has fewer parts, and is relatively easy to process and assemble, resulting in low manufacturing costs, which is beneficial for practical industrial applications and large-scale mass production.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to an axially split-phase magnetically enhanced three-phase high-speed switched reluctance motor based on toothed cogging magnetization. Technical Background

[0002] Switched reluctance motors originated in Britain in the 1840s, but due to the use of mechanical switches in drive systems at that time, their operating characteristics and energy conversion efficiency were low, and they did not receive the attention they deserved. It wasn't until the 1960s, with the use of high-power thyristors, that reluctance motors experienced rapid development. The working principle of a reluctance motor is that the magnetic field always travels along the path of least magnetic reluctance, i.e., the "principle of least magnetic reluctance." When the rotor rotates, the magnetic field is distorted, generating a tangential magnetic pull, forming torque. According to the working principle of the reluctance motor, the magnetic permeability of the magnetic circuit varies depending on the relative position of the stator and rotor teeth, and the rotation of the rotor ensures that the magnetic reluctance of the magnetic circuit is minimized; changing the energizing sequence of the coils ensures continuous rotation of the motor. Therefore, switched reluctance motors are characterized by simple structure, low cost, and high reliability. Currently, reluctance motors are widely used in hub motors of electric vehicle drive systems and hydraulic pump drive motors in electro-hydraulic servo and speed control systems.

[0003] Switched reluctance motors (SRMs) have specific requirements for driving hydraulic pumps. Ordinary SRMs are mostly dry-type, meaning the stator windings cannot directly contact the hydraulic fluid. However, for pump-specific SRMs, a dry-type motor drive requires a rotary dynamic seal on one side of the pump shaft. Prolonged high-speed pump operation accelerates seal wear and failure, leading to oil leakage from the pump housing. Furthermore, frictional heat can cause the seal to age and crack, and the resulting debris can easily cause malfunctions. As hydraulic pump speeds continue to increase, the rotary dynamic seal at this critical structural point will increasingly become a safety hazard. A fully submerged design, immersing the motor rotor in hydraulic fluid, is becoming the norm, necessitating research and improvement studies on wet-type designs for existing SRMs.

[0004] Reluctance motors can be classified into radially phased and axially phased types based on the spatial distribution of their stator phases. Radially phased reluctance motors are widely used in modern industry due to their compact structure and high power-to-weight ratio. On the other hand, while axially phased motors are slightly larger, their stator phases are arranged along the motor axis, making it easy to construct a simple, high-pressure wet-type structure using O-rings. This gives them a unique advantage when used as drive motors for various hydraulic pumps: they allow the working medium (oil) to enter the rotor cavity, eliminating the need for the inherent dynamic seal on the pump shaft and significantly improving pump reliability. However, because the motor rotor is fully submerged in the working medium, contact between the motor and the oil during rotation causes churning losses, resulting in a considerable reduction in output torque. Therefore, when considering the use of axially phased switched reluctance motors in wet applications driving hydraulic pumps, the focus should be on enhancing their output torque. Summary of the Invention

[0005] To address the aforementioned technical problems in the existing technology, this invention provides an axially split-phase magnetic force-enhanced three-phase high-speed switched reluctance motor based on tooth slot insertion magnetization. By designing the stator and rotor tooth surface structure, the working air gap magnetic flux is increased when the stator teeth are aligned with the rotor teeth, and decreased when the stator teeth are aligned with the rotor slots, thereby increasing the effective magnetic flux and thus improving the electromagnetic torque.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A three-phase high-speed switched reluctance motor based on cogging magnetization and axially split-phase magnetic enhancement includes a front cover, a rear cover, a stator assembly, a rotor assembly, and control coils. The front and rear covers are respectively mounted on the front and rear sides of the stator assembly. The rotor assembly is installed inside the stator assembly, and a rotor shaft is mounted on the rotor assembly. One end of the rotor shaft is connected to the front cover, and the other end passes through the rear cover and protrudes outside the housing. The centerlines of the stator assembly, rotor assembly, and rotor shaft are located on the same straight line, i.e., coaxially arranged. Its characteristic is that…

[0008] The stator assembly includes a first stator, a second stator, a third stator, and a fourth stator. The first stator and the fourth stator have the same shape and each has an annular groove in the middle. The second stator and the third stator have the same shape and each has two annular grooves at both ends in the middle. The inner circular surfaces of the first stator, the second stator, the third stator, and the fourth stator have the same number of stator teeth and stator tooth slots evenly distributed circumferentially and arranged at intervals. The stator teeth form the stator magnetic surface. The annular grooves at one end of the first stator and the second stator face each other and their outer rings fit together to form a first symmetrical groove. The annular grooves at the other end of the second stator and the third stator face each other and their outer rings fit together to form a second symmetrical groove. The annular grooves at the other end of the third stator and the fourth stator face each other and their outer rings fit together to form a third symmetrical groove. Coil holders for mounting control coils are installed in the first symmetrical groove, the second symmetrical groove, and the third symmetrical groove.

[0009] The control coil includes a first control coil, a second control coil, and a third control coil. The first control coil, the second control coil, and the third control coil are respectively mounted on coil holders in the first symmetrical groove, the second symmetrical groove, and the third symmetrical groove to form a control magnetic flux.

[0010] The rotor assembly is in three sections, including a first rotor, a second rotor, and a third rotor with identical structures. The outer circumferential surfaces of the first, second, and third rotors have rotor teeth with the same number and shape as the stator teeth, forming rotor magnetic surfaces. The outer circumferential surfaces of the first, second, and third rotors have evenly distributed rotor tooth slots spaced at intervals from the rotor teeth. The rotor teeth on the first, second, and fourth rotors are staggered from each other circumferentially by 1 / 3 tooth pitch angle. The first rotor forms a working air gap δ1 with the first stator, a working air gap δ2 with the second stator, a working air gap δ3 with the second stator, a working air gap δ4 with the third stator, a working air gap δ5 with the third stator, and a working air gap δ6 with the fourth stator.

[0011] The permanent magnet strip includes a stator insert permanent magnet strip and a rotor insert permanent magnet strip. The stator insert permanent magnet strip is inserted into the stator slots of the first stator, second stator, third stator, and fourth stator, and the rotor insert permanent magnet strip is inserted into the rotor slots of the first rotor, second rotor, and third rotor. Both the stator insert permanent magnet strip and the rotor insert permanent magnet strip are radially magnetized, so that the polarity of the slot opening is opposite to the polarity of the tooth tip.

[0012] Furthermore, the rotor shaft is a stepped shaft, connected to the rotor key, and supported between the front end cover and the rear end cover by bearings.

[0013] Furthermore, the front end cover, rear end cover, and rotor shaft are all made of non-magnetic metal materials.

[0014] Furthermore, the first rotor, second rotor, third rotor, first stator, second stator, third stator, and fourth stator are all made of soft magnetic metal material with high magnetic permeability.

[0015] The beneficial effects of this invention are mainly reflected in:

[0016] 1. A special stator and rotor tooth surface structure is adopted, and permanent magnet strips are filled in the stator and rotor tooth slots. This invention increases the working air gap magnetic flux when the stator teeth are aligned with the rotor teeth by designing the stator and rotor tooth surface structure; and decreases the working air gap magnetic flux when the stator teeth are aligned with the rotor slots, thereby increasing the effective magnetic flux and thus improving the electromagnetic torque.

[0017] 2. Simple structure and low cost. Compared with other motors, the solution provided by this invention has fewer parts, and is easier to process and assemble, resulting in lower manufacturing costs and making it suitable for practical industrial applications and large-scale mass production. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the overall structure assembly of the present invention;

[0020] Figure 3 This is a schematic diagram of the rotor shaft structure of the present invention;

[0021] Figure 4 This is a schematic diagram of the front cover of the present invention;

[0022] Figure 5a This is a schematic diagram of the rotor structure of the present invention;

[0023] Figure 5b This is a schematic diagram of the assembly of the rotor and permanent magnet strip of the present invention;

[0024] Figure 6a This is a schematic diagram of the first stator structure of the present invention;

[0025] Figure 6b This is a schematic diagram of the assembly of the first stator and the permanent magnet strip of the present invention;

[0026] Figure 7a This is a schematic diagram of the second stator structure of the present invention;

[0027] Figure 7b This is a schematic diagram of the assembly of the second stator and the permanent magnet strip of the present invention;

[0028] Figure 8This is a schematic diagram of the coil cage structure of the present invention;

[0029] Figure 9 This is a schematic diagram of the rear end cover of the present invention;

[0030] Figure 10a This is an assembly diagram of the first stator and the first rotor of the present invention;

[0031] Figure 10b This is a schematic diagram of the assembly of the second stator and the first rotor of the present invention;

[0032] Figure 10c This is an assembly diagram of the second stator and the second rotor of the present invention;

[0033] Figure 10d This is an assembly diagram of the third stator and the second rotor of the present invention;

[0034] Figure 10e This is an assembly diagram of the third stator and the third rotor of the present invention;

[0035] Figure 10f This is an assembly diagram of the fourth stator and the third rotor of the present invention;

[0036] Figure 11a This is a schematic diagram of the polarity of the permanent magnet strips of the stator at air gaps δ1, δ3, and δ5 of the present invention.

[0037] Figure 11b This is a schematic diagram of the polarity of the permanent magnet bars of the rotor at air gaps δ1, δ3, and δ5 of the present invention.

[0038] Figure 11c This is a schematic diagram of the polarity of the permanent magnet strips of the stator at air gaps δ2, δ4, and δ6 of the present invention.

[0039] Figure 11d This is a schematic diagram of the polarity of the permanent magnet bars of the rotor at air gaps δ2, δ4, and δ6 of the present invention;

[0040] Figure 12 This is a schematic diagram of the working principle of the present invention. The first control coil, the second control coil, and the third control coil are all de-energized.

[0041] Figure 13 This is a schematic diagram showing the relative positions of the stator and rotor of the present invention. The first control coil, the second control coil, and the third control coil are all de-energized.

[0042] Figure 14a This is a schematic diagram of the working principle of the present invention, in which only the second control coil is supplied with positive current;

[0043] Figure 14bThis is an enlarged view of the magnetic circuit of the present invention, showing the magnetic circuit at air gap δ1 and air gap δ2 at the instant when the second control coil is supplied with a positive current.

[0044] Figure 14c This is a schematic diagram showing the relative positions of the stator and rotor of the present invention, with only the second control coil energized with positive current;

[0045] Figure 14d This is an enlarged view of the magnetic circuit of the present invention, showing the magnetic circuit at air gaps δ1 and δ2 after the rotor moves, with only the second control coil carrying a positive current.

[0046] Figure 14e This is a schematic diagram of the working principle of the present invention, in which only the third control coil is supplied with positive current;

[0047] Figure 14f This is a schematic diagram showing the relative positions of the stator and rotor of the present invention, with only the third control coil energized with positive current;

[0048] Figure 14g This is a schematic diagram of the working principle of the present invention, in which only the first control coil is supplied with positive current;

[0049] Figure 14h This is a schematic diagram showing the relative positions of the stator and rotor of the present invention, with only the first control coil having a positive current applied. Detailed Implementation Plan

[0050] The invention will now be further described with reference to the accompanying drawings.

[0051] Reference Figures 1-14h The present invention discloses an axially split-phase magnetic force-enhanced three-phase high-speed switched reluctance motor based on toothed cogging magnetization, comprising a front cover 2, a rear cover 15, a stator component, a rotor component, and a control coil. The front cover 2 and the rear cover 15 are respectively mounted on the front and rear sides of the stator component. The rotor component is installed inside the stator component, and a rotor shaft 1 is mounted on the rotor component. One end of the rotor shaft 1 is connected to the front cover 2, and the other end passes through the rear cover 15 and is exposed outside the housing. The centerlines of the stator component, the rotor component, and the rotor shaft 1 are located on the same straight line, i.e., coaxially arranged.

[0052] The stator component of this invention comprises a first stator 4, a second stator 7, a third stator 9, and a fourth stator 12. The first stator 4 and the fourth stator 12 have identical shapes, as do the second stator 7 and the third stator 9. The inner surfaces of the first stator 4, the second stator 7, the third stator 9, and the fourth stator 12 have an equal number of stator teeth and stator slots evenly distributed circumferentially, forming a stator magnetic surface. Each stator inner circle has 15 stator teeth and 15 stator slots evenly distributed circumferentially, forming a stator magnetic surface. A stator insert permanent magnet strip 41 is axially mounted in one of the 15 stator slots of the first stator 4 and the fourth stator 12. Figure 6b As shown, the second stator 7 and the third stator have two stator permanent magnet strips 41 of the same length installed axially in the 15 stator slots. Figure 7b As shown. An annular groove is formed between the first stator 4 and the fourth stator 12. Two annular grooves are formed at both ends of the second stator 7 and the third stator 9. The annular grooves at one end of the first and second stators face each other and their outer rings fit together to form a first symmetrical groove. The annular grooves at the other end of the second stator face each other and their outer rings fit together to form a second symmetrical groove. The annular grooves at the other end of the third stator face each other and their outer rings fit together to form a third symmetrical groove. A coil holder 13 is placed in each of the first, second, and third symmetrical grooves, and a control coil is wound on the coil holder 13. The stator insertion permanent magnet strips 41 in the stator slots are radially magnetized, with polarity opposite to the direction of the magnetic flux generated by the control coil. The permanent magnet strip in the slot of the first stator 4 has an S polarity at the slot end and an N polarity at the slot bottom end, as shown. Figure 11a As shown. The permanent magnet bar slot ends in the second stator 7, opposite the first rotor 3, have N polarity at the slot end and S polarity at the slot bottom end, as shown. Figure 11c As shown, the polarity of the permanent magnet bar slot end opposite to the second rotor 6 in the slot of the second stator 7 is S polarity, and the polarity of the bottom end of the slot is N polarity, as shown. Figure 11a As shown. The permanent magnet bar slot end opposite the second rotor 6 within the slot of the third stator 9 has a north (N) polarity, while the bottom end of the slot has a south (S) polarity, as illustrated. Figure 11c As shown, the polarity of the permanent magnet bar slot end opposite to the third rotor 10 in the third stator 9 slot is S polarity, and the polarity of the bottom end of the slot is N polarity, as shown. Figure 11a As shown. The polarity of the permanent magnet bar slot end in the fourth stator 12 slot is S polarity, and the polarity of the bottom end of the slot is N polarity, as shown. Figure 11c As shown, permanent magnet strips are placed in the stator slots, which prevent the magnetic lines of force generated by the control coil from passing through the stator slots to the rotor. Secondly, they concentrate towards the stator teeth, so that when the stator teeth face the rotor teeth, the magnetic flux entering the rotor teeth increases, and when the stator slots face the rotor teeth, the magnetic flux entering the rotor teeth decreases, thus increasing the alternating component of the magnetic flux, i.e., the effective magnetic flux.

[0053] The rotor assembly is a three-section unit, comprising a first rotor 3, a second rotor 6, and a third rotor 10 with identical structures. Each rotor has 15 rotor teeth and 15 rotor slots evenly distributed along its outer circumference. Rotor slots are fitted with rotor-inserted permanent magnet strips 31. Figure 5bAs shown. The rotor teeth form the rotor magnetic surface, and the rotor magnetic surface and the stator magnetic surface form the working air gap. To enable the motor to rotate continuously, the radial tooth staggering of the three rotor segments needs to be changed. The arrangement is as follows: the first rotor 3 and the second rotor 6 are radially staggered by 1 / 3 tooth pitch angle, and the second rotor 6 and the third rotor 10 are radially staggered by 1 / 3 tooth pitch angle, as shown. Figures 10a to 10f As shown. Each rotor segment has 15 rotor slots, each equipped with two identical rotor magnet strips 31 along the axial direction, as shown. Figure 5b As shown, the rotor's inserted permanent magnet strip 31 is radially magnetized, with its polarity opposite to the direction of the magnetic flux generated by the control coil. The permanent magnet strip's slot end, opposite to the first stator 4, has a north (N) polarity, while the slot bottom end has a south (S) polarity. Figure 11b As shown, the polarity of the permanent magnet slot end opposite to the second stator 7 in the slot of the first rotor 3 is S polarity, and the polarity of the bottom end of the slot is N polarity, as shown. Figure 11d As shown. The permanent magnet bar slot ends in the second rotor 6, opposite the second stator 7, have N polarity at the slot ends and S polarity at the slot bottom ends, as shown. Figure 11b As shown, the polarity of the permanent magnet slot end opposite to the third stator 9 in the second rotor 6 slot is S polarity, and the polarity of the bottom end of the slot is N polarity. Figure 11d As shown. The permanent magnet slot ends opposite the third stator 9 within the slot of the third rotor 10 have N polarity, while the bottom ends have S polarity, as illustrated. Figure 11b As shown, the polarity of the permanent magnet slot end opposite to the fourth stator 12 in the slot of the third rotor 10 is S polarity, and the polarity of the bottom end of the slot is N polarity, as shown. Figure 11d As shown, permanent magnet strips are placed inside the rotor slots, which prevent the magnetic lines of force generated by the control coil from reaching the stator through the slots. Instead, they concentrate towards the rotor teeth, increasing the magnetic flux entering the stator teeth when the rotor teeth face the stator teeth and decreasing the magnetic flux entering the stator teeth when the rotor slots face the stator teeth. This increases the crossover component of the magnetic flux, i.e., the effective magnetic flux.

[0054] In one embodiment, the rotor shaft 1 is a stepped shaft connected to the rotor key and supported between the front end cover 2 and the rear end cover 15 by bearing 14.

[0055] In one embodiment, the front end cover 2, the rear end cover 15, and the rotor shaft 1 are all made of non-magnetic metal material, while the first rotor, the second rotor, the third rotor, the first stator 4, the second stator 7, the third stator 9, and the fourth stator 12 are all made of soft magnetic metal material with high magnetic permeability.

[0056] like Figures 12-13 As shown, when the coil is not energized, the rotor component is in its initial position.

[0057] When the second control coil 8 is energized as follows Figure 14a With the positive current shown, the first control coil 5 and the third control coil 11 are not energized. Magnetic flux is generated at the working air gap δ3 between the second stator 7 and the second rotor 6, and at the working air gap δ4 between the third stator 9 and the second rotor 6. At this time, the magnetic circuits at the working air gaps δ3 and δ4 are as follows: Figure 14b As shown, the rotor component rotates through 1 / 3 of a tooth pitch under a clockwise torque, as... Figure 14c As shown, the magnetic circuits at working air gaps δ3 and δ4 change at this time, as follows: Figure 14d As shown.

[0058] Then, the third control coil 11 is energized as follows: Figure 14e The positive current shown de-energizes the first control coil 5 and the second control coil 8. Magnetic flux is generated at the working air gap δ5 between the third stator 9 and the third rotor 10, and at the working air gap δ6 between the fourth stator 12 and the third rotor 10. The rotor components rotate clockwise by 1 / 3 of a tooth pitch. Figure 14f As shown.

[0059] Next, the first control coil 5 is energized as follows: Figure 14g The positive current shown de-energizes the second control coil 8 and the third control coil 11. Magnetic flux is generated at the working air gap δ1 between the first stator 4 and the first rotor 3, and at the working air gap δ2 between the second stator 7 and the first rotor 3. The first rotor rotates clockwise through 1 / 3 of a tooth pitch under a clockwise torque. Figure 14h As shown. By repeating the above energizing method, the rotor component will continuously rotate in steps of 1 / 3 tooth pitch angle; by changing the energizing method, the rotor component can move in the opposite direction; if a control method similar to that of a synchronous motor is adopted, the rotor component can achieve smooth and uniform continuous rotation.

[0060] The above specific embodiments are used to explain the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. An axially split-phase magnetically enhanced three-phase high-speed switched reluctance motor based on toothed cogging magnetization, comprising a front cover, a rear cover, a stator assembly, a rotor assembly, and control coils, wherein the front cover and rear cover are respectively mounted on the front and rear sides of the stator assembly, the rotor assembly is installed inside the stator assembly, a rotor shaft is mounted on the rotor assembly, one end of the rotor shaft is connected to the front cover, and the other end passes through the rear cover and protrudes outside the housing, the centerlines of the stator assembly, the rotor assembly, and the rotor shaft are located on the same straight line, i.e., coaxially arranged; characterized in that, The stator assembly includes a first stator, a second stator, a third stator, and a fourth stator. The first stator and the fourth stator have the same shape and each has an annular groove in the middle. The second stator and the third stator have the same shape and each has two annular grooves at both ends in the middle. The inner circular surfaces of the first stator, the second stator, the third stator, and the fourth stator have the same number of stator teeth and stator tooth slots evenly distributed circumferentially and arranged at intervals. The stator teeth form the stator magnetic surface. The annular grooves at one end of the first stator and the second stator face each other and their outer rings fit together to form a first symmetrical groove. The annular grooves at the other end of the second stator and the third stator face each other and their outer rings fit together to form a second symmetrical groove. The annular grooves at the other end of the third stator and the fourth stator face each other and their outer rings fit together to form a third symmetrical groove. Coil holders for mounting control coils are installed in the first symmetrical groove, the second symmetrical groove, and the third symmetrical groove. The control coil includes a first control coil, a second control coil, and a third control coil. The first control coil, the second control coil, and the third control coil are respectively mounted on coil holders in the first symmetrical groove, the second symmetrical groove, and the third symmetrical groove to form a control magnetic flux. The rotor assembly is in three sections, including a first rotor, a second rotor, and a third rotor with identical structures. The outer circumferential surfaces of the first rotor, the second rotor, and the third rotor have rotor teeth with the same number and shape as the stator teeth, forming rotor magnetic surfaces. The outer circumferential surfaces of the first rotor, the second rotor, and the third rotor have rotor tooth slots that are evenly distributed and spaced apart from the rotor teeth. The rotor teeth on the first rotor, the second rotor, and the fourth rotor are staggered from each other by 1 / 3 tooth pitch angle in the circumferential direction. The first rotor forms a working air gap δ1 with the first stator, the first rotor forms a working air gap δ2 with the second stator, the second rotor forms a working air gap δ3 with the second stator, the second rotor forms a working air gap δ4 with the third stator, the third rotor forms a working air gap δ5 with the third stator, and the third rotor forms a working air gap δ6 with the fourth stator. The permanent magnet strip includes a stator insert permanent magnet strip and a rotor insert permanent magnet strip. The stator insert permanent magnet strip is inserted into the stator slots of the first stator, second stator, third stator, and fourth stator, and the rotor insert permanent magnet strip is inserted into the rotor slots of the first rotor, second rotor, and third rotor. Both the stator insert permanent magnet strip and the rotor insert permanent magnet strip are radially magnetized, so that the polarity of the slot opening is opposite to the polarity of the tooth tip.

2. The axially split-phase magnetically enhanced three-phase high-speed switched reluctance motor based on toothed cogging magnetization as described in claim 1, characterized in that, The rotor shaft is a stepped shaft, which is keyed to the rotor and supported by bearings between the front cover and the rear cover.

3. The axially split-phase magnetically enhanced three-phase high-speed switched reluctance motor based on toothed cogging magnetization as described in claim 1, characterized in that, The front cover, rear cover, and rotor shaft are all made of non-magnetic metal materials.

4. The axially split-phase magnetically enhanced three-phase high-speed switched reluctance motor based on toothed cogging magnetization as described in claim 1, characterized in that, The first rotor, second rotor, third rotor, first stator, second stator, third stator, and fourth stator are all made of soft magnetic metal material with high magnetic permeability.

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