Permanent magnet motor rotor punching sheet with high energy efficiency level

Abstract

The utility model discloses a high energy efficiency grade permanent magnet motor rotor punching sheet, comprising a rotating shaft, a rotor punching sheet and magnetic steel, the rotating shaft is sleeved with the rotor punching sheet, the rotor punching sheet is circumferentially and uniformly provided with a plurality of arc-shaped magnetic steel grooves in a surrounding manner, the magnetic steel is embedded in the arc-shaped magnetic steel grooves, and the magnetic steel comprises an arc-shaped body. The arc-shaped surface magnetic steel can be closer to the surface of the rotor, the salient pole rate of the rotor is low, the rotor is easy to control, and the radiuses of the upper arc and the lower arc of the arc-shaped body are R1 and R2, R2gt; reverse chamfer angles used for adjusting the air gap flux density shape of the magnetic steel are designed on the two sides of the arc-shaped body, the arc radius R3 of the reverse chamfer angles is larger than or equal to 7 and larger than or equal to 3. Through the above mode, the utilization rate of the rotor magnetic steel is improved, the performance of the magnetic steel can be fully exerted, and the surface air gap flux density of the rotor is improved, so that the energy efficiency of the motor is improved, and the effects of energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of motor parts, in particular to a high-efficiency permanent magnet motor rotor punching sheet. Background Art

[0002] Energy conservation and emission reduction is an inescapable topic in today's world, which affects the development of the world economy. As an important industrial field for energy conservation and emission reduction, among them, the motor system has great potential for energy conservation. Its electricity consumption accounts for about 40% of the total industrial electricity consumption in the country. Permanent magnet synchronous motors are widely used in various general mechanical equipment such as fans, pumps, compressors, belt conveyors, and mills in major industrial fields due to their more efficient and energy-saving characteristics compared with asynchronous motors. The rotor structure of permanent magnet synchronous motors determines the characteristics of permanent magnet synchronous motors. Currently, the more commonly used rotor structures are surface-mounted and embedded structures. The permanent magnet synchronous rotor with a surface-mounted magnetic steel structure is as Figure 1 shown, and the permanent magnet synchronous rotor with an embedded magnetic steel structure is as Figure 2 shown, which includes a rotating shaft a, a rotor punching sheet b, a magnetic steel c, and a magnetic steel retaining ring d. Currently, the permanent magnet synchronous motor rotors all have the problem of low utilization rate of magnetic steel, which reduces the motor efficiency, increases the motor loss, and results in the motor energy efficiency not reaching the energy efficiency level of the national standard.

[0003] Based on the above defects and deficiencies, it is necessary to improve the existing technology and design a high-efficiency permanent magnet motor rotor punching sheet. Summary of the Utility Model

[0004] The main technical problem to be solved by the utility model is to provide a high-efficiency permanent magnet motor rotor punching sheet, which can improve the utilization rate of the rotor magnetic steel, give full play to the performance of the magnetic steel, increase the air-gap magnetic density on the rotor surface, thereby improving the energy efficiency of the motor and achieving the effect of energy conservation and emission reduction.

[0005] To solve the above technical problems, a technical solution adopted by the present utility model is: to provide a high-efficiency permanent magnet motor rotor punching sheet. This high-efficiency permanent magnet motor rotor punching sheet includes a rotating shaft, a rotor punching sheet, and a permanent magnet. The rotating shaft is externally sleeved with the rotor punching sheet. A number of arc-shaped magnet slots are circumferentially and evenly arranged around the rotor punching sheet. The arc-shaped magnet slots are internally embedded with permanent magnets. The permanent magnet includes an arc-shaped body. The arc-shaped surface permanent magnet can be closer to the rotor surface. The rotor salient pole rate is low and it is easy to control. The upper and lower arc radii of the arc-shaped body are R1 and R2, and R2 > R1 + 3. The two sides of the arc-shaped body are designed with reverse chamfers for adjusting the air-gap magnetic density shape of the permanent magnet. The arc radius of the reverse chamfer is R3, 7 ≥ R3 ≥ 3. When the permanent magnet has reverse chamfers, the magnetic field at the alternating N and S poles of the permanent magnet does not change suddenly, and the air-gap magnetic density waveform is relatively smooth. Thus, the cogging effect of the motor can be reduced, indirectly improving the torque stability of the motor at low speeds and enhancing the servo performance of the motor.

[0006] Preferably, the arc-shaped magnet slot includes an arc-shaped slot and cavity slots protruding on both sides of the arc-shaped slot. The upper and lower sides of the arc-shaped body are clamped at the upper and lower ends of the arc-shaped slot. The cavity slot and the reverse chamfer form a gap cavity. The gap cavity is used to reduce the amplitude of the high-order harmonics of the motor back electromotive force waveform. The upper and lower arc radii of the arc-shaped slot are r1 and r2, r2 > r1 + 5. Through simulation calculation, the results obtained by simulating different motor rotors show that when r2 > 20, r2 > r1 + 5, the sinusoidality of the motor back electromotive force waveform is better, and the proportion of the amplitude of each high-order harmonic can be reduced to less than 2%.

[0007] Preferably, the arc-shaped body is designed with increased thickness and width. Adjacent arc-shaped bodies are closely arranged, which can increase the projection area of the permanent magnet. With a large permanent magnet area, under the condition of the same back electromotive force coefficient, the stator inductance can be reduced, thereby improving the voltage utilization rate of the motor and enhancing the motor performance.

[0008] Compared with the prior art, the beneficial effects of the present utility model are:

[0009] (1) Through the arc-shaped embedded rotor structure and the use of the arc-shaped permanent magnet structure, the pole arc coefficient of the permanent magnet of the motor can be improved. A large pole arc coefficient is equivalent to increasing the use area of the permanent magnet, improving the air-gap magnetic field on the rotor surface, increasing the motor torque, and thus effectively improving the motor efficiency;

[0010] (2) Through the optimization of the dimensions R1, R2, and R3 of the permanent magnet and the rotor punching sheet, the air-gap magnetic field is made uniform, the static cogging torque of the motor is reduced, the amplitude of the high-order harmonics is reduced, the harmonic loss is reduced, the motor efficiency is further improved, and the energy loss is reduced. Description of the Drawings

[0011] Figure 1 It is a sectional view of a surface-mounted permanent magnet structure permanent magnet synchronous rotor.

[0012] Figure 2 It is a sectional view of a permanent magnet synchronous rotor with an embedded magnetic steel structure.

[0013] Figure 3 It is a schematic diagram of the assembled structure of a rotor punching sheet of a high-efficiency permanent magnet motor.

[0014] Figure 4 It is a sectional view of the assembled rotor punching sheet of a high-efficiency permanent magnet motor.

[0015] Figure 5 It is a projection view of the outer shape of the rotor punching sheet.

[0016] Figure 6 It is a projection view of the outer shape of the magnetic steel.

[0017] Figure 7 It is a comparison diagram of the back electromotive force waveforms of motors of Scheme A and B.

[0018] Figure 8 It is a comparison of the high-order harmonic numerical values of the back electromotive force of Scheme A and B.

[0019] Figure 9 It is a comparison diagram of the cogging torque of motors of Scheme A and B.

[0020] Figure 10 It is the output torque-speed curve of motors of Scheme A and B.

[0021] Among them, 1 is the rotating shaft, 2 is the rotor punching sheet, 20 is the arc-shaped magnetic steel groove, 201 is the arc-shaped groove, 202 is the cavity groove, 3 is the magnetic steel, 31 is the arc-shaped body, 32 is the reverse chamfer, and 4 is the clearance cavity. Specific implementation mode

[0022] The following combines the attached drawings to elaborate on the preferred embodiments of the present invention in detail, so that the advantages and features of the invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0023] Please refer to Figures 3 to 10 , the embodiments of the present invention include:

[0024] A rotor punching sheet of a high-efficiency permanent magnet motor, which includes a rotating shaft 1, a rotor punching sheet 2, and a magnetic steel 3. The rotor punching sheet 2 is sleeved outside the rotating shaft 1. Eight arc-shaped magnetic steel grooves 20 are circumferentially and uniformly arranged around the rotor punching sheet 2. The arc-shaped magnetic steel grooves 20 are internally equipped with magnetic steel 3. The magnetic steel 3 includes an arc-shaped body 31, relative to Figure 2For the magnet steel on the middle plane, the arc-shaped magnet steel can be closer to the rotor surface. The rotor salient pole rate is low and it is easy to control. The arc-shaped body 31 is designed with increased thickness and width, and two adjacent arc-shaped bodies 31 are closely arranged, which can increase the projected area of the magnet steel. With a large magnet steel area, under the condition of the same back electromotive force coefficient, the stator inductance can be reduced, thereby improving the motor voltage utilization rate and motor performance. The upper and lower arc radii of the arc-shaped body 31 are R1 and R2, and R2 > R1 + 3. The two sides of the arc-shaped body 31 are designed with reverse chamfers 32 for adjusting the air-gap magnetic density shape of the magnet steel. The arc radius of the reverse chamfer 32 is R3, and 7 ≥ R3 ≥ 3. When the magnet steel has reverse chamfers, the magnetic field at the alternating N and S poles of the magnet steel does not change suddenly, and the air-gap magnetic density waveform is relatively smooth, which can reduce the cogging effect of the motor and indirectly improve the torque stability of the motor at low speed, improving the servo performance of the motor.

[0025] The arc-shaped magnet steel slot 20 includes an arc-shaped slot 201 and cavity slots 202 protruding from both sides of the arc-shaped slot 201. The upper and lower sides of the arc-shaped body 31 are clamped at the upper and lower ends of the arc-shaped slot 201. The cavity slot 202 and the reverse chamfer 32 form a gap cavity 4, and the gap cavity 4 is used to reduce the amplitude of the high-order harmonics of the motor back electromotive force waveform. The upper and lower arc radii of the arc-shaped slot 201 are r1 and r2, and r2 > r1 + 5. Through simulation calculation and the results obtained by simulating different motor rotors, when r2 > 20, r2 > r1 + 5, the sinusoidality of the motor back electromotive force waveform is better, and the proportion of the amplitude of each high-order harmonic can be reduced to less than 2%.

[0026] Regarding the data of the motor design, here is a list of a motor of the 18 series of a company. Its design parameters are R1 = 39, R2 = 47, and R3 = 4. Here, R1, R2, and R3 are optimized and meet the requirements of R2 > R1 + 5 and 7 ≥ R3 ≥ 3, which is called Plan A. Another design comparison Plan B: Its rotor R1 = R2 = 39 and R3 = 0, which does not meet the requirements of R2 > R1 + 5 and 7 ≥ R3 ≥ 3.

[0027] Comparison of the motor back electromotive force waveforms, as Figure 7 shown: The red one is the back electromotive force waveform of Plan A, and the blue one is the back electromotive force waveform of Plan B. It can be seen from the waveforms that the waveform of Plan A is smooth and has better sinusoidality, while the waveform of Plan B has protrusions and concavities and poor sinusoidality.

[0028] Comparison of the high-order harmonic values of the back electromotive force, as Figure 8 shown: The values on the left side of the table are for Plan A, and the values on the right side are for Plan B. It can be seen from the table that the effective fundamental wave (1st wave) value of Plan A is larger at 314V, and the effective fundamental wave (1st wave) value of Plan B is smaller at 305V, so Plan A is better; it can be seen that the amplitudes of the 5th, 7th, 17th, and 9th harmonics of Plan B are larger, while the amplitudes of the high-order harmonics of the patented Plan A are all smaller, so Plan A is better.

[0029] Comparison of cogging torque of the motor is as follows Figure 9 shown: The red curve is the cogging torque of Scheme A, with a maximum value of 0.01 N·m. The blue curve is the cogging torque of Scheme B, with a maximum value of 0.06 N·m. Although both can meet the general design requirements, the value of Scheme A is smaller and the low-speed control performance is better.

[0030] Comparison of the output torque of the motor. Let the motor be loaded with a current of 32 A. The torque-speed curve of the motor output is as follows Figure 10 shown: The red curve is the torque-speed curve of Scheme A, with a maximum torque of 119 N·m. The blue curve is the torque-speed curve of Scheme B, with a maximum torque of 116 N·m. Scheme A is also superior to Scheme B.

[0031] In summary, the performance of the motor of Patent Scheme A is superior to that of the scheme that does not meet the patent requirements.

[0032] The optimization of R1, R2, and R3 is part of the design of the motor rotor. By using simulation software to adjust different R1, R2, and R3, different design results can be obtained on the software: cogging torque, high-order harmonics of back electromotive force, back electromotive force waveform, corresponding output torque of the motor, motor speed, motor power, motor efficiency, etc. The designer needs to make a comprehensive evaluation of each index according to the design requirements. When the values of R1, R2, and R3 are different, the changes in cogging torque, high-order harmonics of back electromotive force, back electromotive force waveform, corresponding output torque of the motor, motor speed, motor power, etc. are not in the same direction.

[0033] The rotor punching sheet of the high-efficiency permanent magnet motor of the present utility model improves the utilization rate of the rotor permanent magnet, can give full play to the performance of the permanent magnet, increases the air-gap magnetic density on the rotor surface, thereby improving the energy efficiency of the motor and achieving the effect of energy conservation and emission reduction.

[0034] The above are only the embodiments of the present utility model, and do not limit the patent scope of the present utility model. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied to other related technical fields, shall be included in the patent protection scope of the present utility model by the same token.

Claims

1. A high energy efficiency grade permanent magnet motor rotor punching sheet, characterized in that: The invention comprises a rotating shaft (1), a rotor punching (2) and a magnetic steel (3), wherein the rotating shaft (1) is externally mounted with a rotor punching (2), the rotor punching (2) is circumferentially evenly provided with a plurality of arc-shaped magnetic steel grooves (20), the arc-shaped magnetic steel grooves (20) are embedded with magnetic steel (3), the magnetic steel (3) comprises an arc-shaped body (31), the upper and lower arc radii of the arc-shaped body (31) are R1 and R2, wherein R2>R1+3, and reverse chamfers (32) for adjusting the air gap magnetic density shape of the magnetic steel are designed on both sides of the arc-shaped body (31), and the arc radius of the reverse chamfer (32) is R3,7≥R3≥3.

2. The high energy efficiency grade permanent magnet motor rotor punching sheet according to claim 1, characterized in that: The arc-shaped magnetic steel slot (20) comprises an arc-shaped slot (201), and a cavity slot (202) disposed on both sides of the arc-shaped slot (201) and protruding. The upper and lower sides of the arc-shaped body (31) are embedded in the upper and lower ends of the arc-shaped slot (201). The cavity slot (202) and the reverse chamfer (32) form a gap cavity (4). The gap cavity (4) is used to reduce the amplitude of the high-order harmonics of the motor back-electromotive force waveform. The upper and lower arc radii of the arc-shaped slot (201) are r1 and r2, and r2>r1+5.

3. The high energy efficiency grade permanent magnet motor rotor punching sheet according to claim 1, characterized in that: The arc-shaped body (31) is designed to be thickened and widened, and two adjacent arc-shaped bodies (31) are arranged closely together.

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