CN103023265A - Bearingless permanent magnet slice motor - Google Patents

Abstract

The invention discloses a bearingless permanent magnet sheet motor. The sheet rotor is located in the inner cavity of the axially upper section of the stator. The sheet rotor is a permanent magnet with S and N poles magnetized in parallel in the radial direction. The stator is uniformly distributed on the sheet rotor along the circumferential direction. There are 6 other stator core columns, each stator core column has the same radial air gap between the inner diameter of the stator core column and the outer diameter of the sheet rotor; in the axial upper part of the stator, one is set in the middle of every two stator core columns Radial displacement sensor probes, 6 radial displacement sensor probes are evenly distributed along the circumferential direction of the sheet rotor, the radial distance between each radial displacement sensor probe and the sheet rotor is the same as the radial air gap; the positive The lower part is equipped with a Hall sensor; in the axial middle of the stator, each stator core column is equipped with a suspension force winding and a torque winding, and a coaxial core yoke is fixed at the bottom of the stator; the motor structure is more compact, reasonable and simple.

Description

A bearingless permanent magnet sheet motor

technical field

The invention is a bearingless permanent magnet synchronous motor, specifically a bearingless permanent magnet sheet motor, which is suitable for many special electrical transmission fields such as sealed pumps, high-speed or ultra-high-speed numerical control machine tools, industrial robots, aerospace, life sciences, etc. It is non-contact, non-lubricating and non-abrasive, and is especially suitable for special occasions such as life sciences, vacuum technology, semiconductor processing, clean rooms, aseptic workshops, and transmission of corrosive media or non-contact and non-polluting liquid media.

Background technique

The bearingless permanent magnet synchronous motor is a new type of motor that integrates the function of the magnetic bearing inside the permanent magnet synchronous motor body. It not only has the advantages of non-contact magnetic bearing, no need for lubrication, long life, etc. High, high power density and other characteristics. In order to realize the complete suspension of five degrees of freedom in addition to the rotation degree of freedom, the bearingless permanent magnet synchronous motor usually needs to be composed of two two-degree-of-freedom bearingless permanent magnet synchronous motor units and an axial magnetic bearing or a three-degree-of-freedom magnetic bearing and a The two-degree-of-freedom bearingless permanent magnet synchronous motor unit is composed of a relatively complex motor mechanical structure; due to the existence of the magnetic bearing, the axial direction of the motor rotor is very long, and the critical speed of the motor rotor is greatly restricted, making it difficult to exert its high-speed or ultra-high-speed performance. characteristic.

In order to make full use of the characteristics of non-contact, no lubrication, long life, high power factor and high power density of the bearingless permanent magnet synchronous motor, and make it practical, a compact structure, Simple, small size and highly practical bearingless alternating pole thin slice motor and single winding bearingless permanent magnet thin slice motor. Among them, the alternating pole bearingless permanent magnet sheet motor is composed of a stator made of laminated silicon steel sheets, a torque winding and a suspension force winding nested in the stator slot, and a sheet rotor. The sheet rotor can be coaxially suspended in the mechanical center of the stator. The lamellar rotor adopts an interpolation structure in which permanent magnets and iron cores are alternately distributed. This structure can realize the complete decoupling of levitation force and torque control. The analysis is difficult, the design of the thickness and size of the permanent magnet is complicated, and the interpolation structure greatly reduces the critical speed of the rotor. At the same time, due to the large number of motor poles and stator slots, the winding installation is difficult; the single-winding bearingless permanent magnet sheet The motor adopts the structure of a 6-tooth stator and a two-pole surface-mounted permanent magnet sheet rotor. The sheet rotor and the stator are coaxially located at the mechanical center of the stator, but only one set of concentrated windings is wound on the 6 teeth of the stator. This winding structure Although the motor can save a certain space in structure, the control system of the motor is complicated and difficult to debug because only one set of winding current generates levitation force and electromagnetic torque at the same time.

Contents of the invention

The purpose of the present invention is to overcome the defects of the above-mentioned prior art, and provide a bearingless permanent magnet with compact and simple structure, which can reduce manufacturing cost and processing difficulty, reduce the complexity of the control system, improve practicability, and improve dynamic working performance. Sheet motor.

In order to achieve the above object, the technical solution adopted by the present invention is: a stator and a sheet rotor coaxial with the stator. The lamellar rotor is located in the inner cavity of the axial upper section of the stator. The lamellar rotor is a permanent magnet with S and N poles magnetized in parallel in the radial direction. The stator is composed of 6 stator core columns uniformly distributed outside the lamellar rotor along the circumferential direction. Each There is the same radial air gap between the inner diameter of the stator core column and the outer diameter of the sheet rotor; on the axial upper section of the stator, a radial displacement sensor probe is installed in the middle of every two stator core columns, and 6 radial displacement sensors The probes are evenly distributed along the circumferential direction of the sheet rotor, and the radial distance between each radial displacement sensor probe and the sheet rotor is the same as the radial air gap; a Hall sensor is set directly below the sheet rotor; in the axial middle of the stator, Each stator core column is covered with a suspension force winding and a torque winding, and a coaxial core yoke is fixed on the bottom of the stator, and the core yoke is closely attached to the bottom end of each stator core column. All stator core columns and core yokes are laminated with silicon steel sheets.

Further, in the axial upper section of the stator, the outer coaxial gap of the thin-plate rotor is covered with a ring-shaped top hard plastic bracket, and the 6 stator core columns and 6 radial displacement sensor probes are embedded in the top hard plastic bracket, and the top hard plastic bracket The inner diameter of the bracket is the same as the inner diameter of the stator, and the outer diameter of the top hard plastic bracket is larger than the outer diameter of the stator; there is a bottom hard plastic bracket coaxially and tightly sleeved on the lower axial section of the stator and the lower part of the winding.

A steel cooling case is coaxially and tightly sleeved outside the top hard plastic bracket and the bottom hard plastic bracket. The bottom surface of the steel cooling case is sealed and connected to the steel chassis. The bottom surface of the yoke is bonded to the top surface of the steel chassis; the top surface of the steel cooling case is connected to the ring-shaped steel top plate, and the top surface of the stator is bonded to the bottom surface of the steel top plate.

The advantages of the present invention are:

1. The present invention adopts the structure of six iron core columns, and the upper and lower layers of two sets of winding components are wound on the six iron core columns, which reduces the radial length of the motor, makes the mechanical structure of the motor more compact, reasonable, simple and practical, and overcomes the single The winding bearingless permanent magnet sheet motor has the defect that the structure is simple but the control system is too complicated.

2. The present invention adopts a two-pole permanent magnet sheet rotor, so that the detection of the rotor magnetic field is simple and reliable, a control strategy based on the rotor magnetic field orientation can be used, and the nonlinear dynamic decoupling control of the radial displacement control subsystem and the speed control subsystem can be realized. The control method It is easy to realize and has strong portability, and at the same time, it gets rid of the defects of the design and manufacture of the alternating pole bearingless permanent magnet sheet motor and the low critical speed of the rotor.

3. Using the magnetic resistance of the bearingless permanent magnet sheet motor itself, the passive suspension control of the three degrees of freedom of the sheet rotor's axial translation and forward and backward, left and right flip movements is realized, which reduces the complexity of the digital control system hardware and control system software; Under the same power or supporting force, the axial length of the motor rotor is greatly reduced, which makes the system have higher power and greater suspension force under the same volume.

Description of drawings

Fig. 1 is the structural front view and the magnetic flux schematic diagram of the bearingless permanent magnet sheet motor of the present invention;

Fig. 2 is B-B direction sectional view in Fig. 1;

Fig. 3 is a schematic diagram of the suspension control principle of the sheet rotor in the bearingless permanent magnet sheet motor of the present invention;

In the figure: 1. Thin rotor hard plastic tray; 2. Torque winding; 3. Stator; 4. Bottom hard plastic bracket; 5. Steel cooling case; 6. Thin rotor; 8. Top hard plastic bracket; 9. Radial suspension force winding; 10. Steel chassis; 11. Bottom iron core yoke; 12. Steel top plate; 13. Hall sensor; 14. Sensor bracket; 15. Cross recessed countersunk head screw; 16. Radial gas Gap; 21. Torque control flux; 61. Torque flux; 71, 72, 73, 74, 75, 76. Displacement sensor probe; 91. Suspension force control flux; 131, 132, 133, 134. Huo Er sensor chip; 301, 302, 303, 304, 305, 306. Stator core column.

Detailed ways

As shown in FIG. 1 and FIG. 2 , the bearingless permanent magnet sheet motor of the present invention has a stator 3 and an annular sheet-shaped sheet rotor 6 . The lamellar rotor 6 is located in the inner cavity of the axially upper part of the stator 3, and the lamellar rotor 6 is a permanent magnet with S and N poles magnetized in parallel in the radial direction, and the material is NdFeB. The stator 3 is composed of six stator core columns 301, 302, 303, 304, 305, and 306, and these six stator core columns 301, 302, 303, 304, 305, and 306 are evenly distributed on the thin-film rotor 6 along the circumferential direction 6 outside, that is, every two stator core columns 301, 302, 303, 304, 305, 306 are separated by 60 degrees, and the inner diameter of each stator core column 301, 302, 303, 304, 305, 306 is the same as that of the sheet rotor 6 The outer diameters all have the same radial air gap 16, which is 2mm. the

At the position of the axial thickness range of the sheet rotor 6, that is, at the axially upper section of the stator 3, a radial displacement sensor is arranged in the middle of every two stator core columns 301, 302, 303, 304, 305, 306 Probes, 6 radial displacement sensor probes 71, 72, 73, 74, 75, 76 are also uniformly distributed along the circumferential direction of the sheet rotor 6, that is, every two radial displacement sensor probes are separated by 60 degrees, and each radial displacement sensor probe is 60 degrees apart. The distance between the displacement sensor probe and its adjacent stator core column is 30 degrees. The radial distance between each radial displacement sensor probe 71, 72, 73, 74, 75, 76 and the sheet rotor 6 is the same as the radial air gap 16, which is 2 mm. When the motor is running, these 6 The radial displacement sensor probes 71 , 72 , 73 , 74 , 75 , and 76 are used to measure the radial displacement of the sheet rotor 6 to form displacement feedback in real time.

A sensor bracket 14 is arranged in the cavity of the stator 3 directly below the thin rotor 6, and the Hall sensor 13 is supported on the sensor bracket 14. The Hall sensor 13 includes 4 Hall sensor chips 131, 132, 133, 134. These 4 The Hall sensor chips 131 , 132 , 133 , 134 are evenly distributed on the sensor support 14 along the circumferential direction, and the interval between every two Hall sensor chips is 90 degrees. By measuring the magnitude and direction of the magnetic field of the sheet rotor 6 through the Hall sensor chip, the magnetic pole position of the sheet rotor 6 and the motor speed can be indirectly measured.

In the axial middle section of the stator 3, each stator core column 301, 302, 303, 304, 305, 306 is provided with two sets of windings, namely the suspension force winding 9 on the upper part and the torque winding on the lower part. 2. The number of pole pairs of the two sets of windings satisfies the relationship of ±1. The iron core yoke 11 is fixed on the axial bottom of the stator 3 , and the iron core yoke 11 and the bottom ends of each stator iron core column 301 , 302 , 303 , 304 , 305 , 306 are tightly attached together. All stator core columns 301 , 302 , 303 , 304 , 305 , 306 and core yoke 11 are formed by laminating silicon steel sheets.

Further, on the axially upper section of the stator 3, an annular top hard plastic bracket 8 is sleeved in the coaxial gap outside the sheet rotor 6, 6 stator core columns 301, 302, 303, 304, 305, 306 and 6 radial Displacement sensor probes 71, 72, 73, 74, 75, 76 are all embedded in the top hard plastic bracket 8, and the inner diameter of the top hard plastic bracket 8 is the same as the inner diameter of the stator 3 surrounded by six stator core columns, and is also the same as the inner diameter of the top hard plastic bracket 8. The diameter of the inner circle surrounded by the six radial displacement sensor probes is the same. The outer diameter of the top hard plastic bracket 8 is larger than that of the stator 3 . The sensor bracket 14 is located at the geometric center of the top hard plastic bracket 8 , and the sensor bracket 14 is fixed on the inner wall of the top hard plastic bracket 8 .

At the axially lower section of the stator 3 and the lower part of the winding, a bottom hard plastic bracket 4 is coaxially and tightly sleeved outside the stator 3 .

Outside the top hard plastic bracket 8 and the bottom hard plastic bracket 4, a steel cooling case 5 is coaxially and tightly sleeved, and the bottom surface of the steel cooling case 5 is connected to the steel chassis 10 with a cross-recessed countersunk head screw 15. , The steel chassis 10 is used to seal the bottom of the motor. The bottom surface of the stator 3 , the bottom surface of the hard plastic bracket 4 and the bottom surface of the iron core yoke 11 are all attached to the top surface of the steel chassis 10 to reduce magnetic flux leakage and loss. The top surface of the steel cooling case 5 is connected to the steel top plate 12 with cross-recessed countersunk head screws 15 , and the top surface of the stator 3 is bonded to the bottom surface of the ring-shaped steel top plate 12 .

A sheet rotor hard plastic tray 1 is inlaid between the sheet rotor 6 and the Hall sensor 13 and between the radial air gap 16 . The opening of the rotor hard plastic tray 1 faces upwards to form a rotor cavity for placing the sheet rotor 6 . Inlay the side wall of the thin rotor hard plastic tray 1 on the inner ring wall of the top hard plastic bracket 8, fix the top surface of the rotor hard plastic tray 1 on the steel top plate 12, and under the thin rotor hard plastic tray 1 is a circular sensor Bracket 14 and Hall sensor 13. The wall thickness of the thin rotor hard plastic tray 1 is 0.4 mm. Since the aforementioned radial air gap 16 is 2 mm, there is a gap of 1.6 mm between the thin rotor hard plastic tray 1 and the thin rotor 6 in the radial direction. The sensor bracket 14 is close to the bottom of the thin rotor hard plastic tray 1 .

Thin rotor hard plastic tray 1, top hard plastic bracket 8, bottom iron core yoke 11, top hard plastic bracket 8, bottom hard plastic bracket 4, steel chassis 10, sensor bracket 14 and steel cooling case 5 are all coaxial, The outer diameter of the steel top plate 12 is the same as the outer diameter of the steel cooling case 5, and the inner diameter of the steel top plate 12 is 4mm larger than the outer diameter of the sheet rotor 6.

As shown in Figures 1-3, the torque flux 61 generated by the slice rotor 6 starts from the N pole of the slice rotor 6, passes through two radial air gaps 16, and two radially opposite stator core columns, that is, radially opposite The two stator core columns 301, 302, or the two radially opposite stator core columns 303, 304, or the radially opposite two stator core columns 305, 306, and the bottom core yoke 11, finally return to the S pole, forming magnetic circuit. The torque control magnetic flux 21 is provided by the torque winding 2 through the three-phase AC current, and a three-phase voltage power inverter is used to drive and control, and the two radially opposite stator core columns, the radial air gap 16, and the sheet A magnetic circuit of torque control flux 21 is formed between the rotor 6 and the bottom iron core yoke 11; the levitation force winding 9 passes a three-phase AC current to provide the levitation force control flux 91, and a three-phase voltage power inverter is used drive control, the levitation force controls the magnetic flux 91 to go upward through the stator core column 303, the radial air gap 16, and enters the sheet rotor 6, and then passes through the radial air gap 16 to the adjacent stator core column 305, and passes through the adjacent stator core column 305. The core column 305 conducts downward and then enters the bottom core yoke 11 , and then returns to 303 , forming a magnetic circuit in which the levitation force controls the magnetic flux 91 . When the motor is running, which stator core columns the levitation force control magnetic flux 91 passes through to form a magnetic circuit depends on the electrical angle of the levitation force control magnetic flux 91 .

Referring to Fig. 3, the present invention uses two sets of concentrated windings to generate torque control magnetic flux 21 and radial levitation force control magnetic flux respectively to complete the active levitation control of two radial degrees of freedom of the slice rotor 6, the axial direction of the slice rotor 6 The three degrees of freedom of translation, forward and backward, and left and right flips are controlled by magnetic resistance according to the principle of minimum magnetic resistance of the magnetic circuit to realize passive suspension control. Specifically: energize the torque winding 2 and the levitation force winding 9, the torque control magnetic flux 21 and the levitation force control magnetic flux 91 are synthesized at the radial air gap 16, so that the air gap magnetic flux at the radial air gap 16 Density distribution is not uniform, according to Maxwell's stress tensor method, will produce radial levitation force F along the negative direction of X axis; similarly, by controlling the phase angle and magnitude of the current in torque winding 2 and levitation force winding 9, the required The radial levitation force F of the slice rotor 6 controls the radial displacement of the slice rotor 6 and realizes active control of the two degrees of freedom of the slice rotor 6; the bearingless permanent magnet slice motor is a kind of permanent magnet motor, and the torque control flux 21 and the torque flux Through 61 synchronous, since the diameter of the thin-film rotor 6 of the motor is smaller than the axial length of the motor, according to the property that the magnetic resistance always minimizes the reluctance of the magnetic circuit, when the thin-film rotor 6 is axially translated or turned left and right (front and back) , the torque control flux 21 and the torque flux 61 will work together to generate a magnetic pull in opposite directions to bring the sheet rotor 6 back to the equilibrium position, thereby realizing the passive control of the sheet rotor 6 with three degrees of freedom; thus, the bearingless Five-degree-of-freedom levitation control of the sheet rotor 6 of the permanent magnet sheet motor.

Claims (6)

1. bearing-free permanent magnet thin-sheet motor, have a stator (3) and a thin slice rotor (6) coaxial with stator (3), thin slice rotor (6) is arranged in the axially inner chamber of epimere of stator (3), it is characterized in that: the S that thin slice rotor (6) magnetizes for radial parallel, N two-poled permanent magnets, stator (3) is comprised of 6 stator core posts that are evenly distributed in the circumferential direction of the circle outside the thin slice rotor (6), has identical radial air gap (16) between each stator core column internal diameter and thin slice rotor (6) external diameter; At the axial epimere of stator (3), the middle of per two stator core posts arranges a radial displacement transducer probe, 6 radial displacement transducers probe evenly distributes along the circumferencial direction of thin slice rotor (6), and each radial displacement transducer probe is all identical with radial air gap (16) with radial distance between the thin slice rotor (6); The positive bottom of thin slice rotor (6) arranges Hall element (13); In the axial stage casing of stator (3), all overlap on each stator core post suspending power winding (9) and torque winding (2) are arranged, stator (3) bottom is fixed with coaxial yoke unshakable in one's determination (11), yoke unshakable in one's determination (11) all is close together with each stator core post bottom, and all stator core posts and yoke unshakable in one's determination (11) all adopt silicon steel plate stacking to form.

2. a kind of bearing-free permanent magnet thin-sheet motor according to claim 1, it is characterized in that: at the axial epimere of stator (3), the outer concentric gap cover of thin slice rotor (6) has the top hard plastic support (8) of annular, 6 stator core posts and 6 radial displacement transducer probes all are embedded in the top hard plastic support (8), top hard plastic support (8) internal diameter is identical with stator (3) internal diameter, and top hard plastic support (8) external diameter is then greater than stator (3) external diameter; Coaxial tight cover has a bottom hard plastic support (4) outside the stator (3) of the axial hypomere of stator (3) and winding lower position.

3. a kind of bearing-free permanent magnet thin-sheet motor according to claim 2, it is characterized in that: coaxial tight cover has a steel radiating machine casing (5) outside top hard plastic support (8) and bottom hard plastic support (4), the steel chassis (10) that is tightly connected on the bottom face of steel radiating machine casing (5), stator (3) bottom surface, bottom hard plastic support (4) bottom surface, yoke unshakable in one's determination (11) bottom surface all fit together with steel chassis (10) end face; Steel radiating machine casing (5) end face connects the steel of annular and takes over a business (12), and stator (3) end face and steel are taken over a business (12) bottom surface and fit together.

4. a kind of bearing-free permanent magnet thin-sheet motor according to claim 2, it is characterized in that: Hall element (13) comprises 4 Hall element chips that are evenly distributed in the circumferential direction of the circle on the sensor stand (14), and sensor stand (14) is fixed on the inwall of top hard plastic support (8).

5. a kind of bearing-free permanent magnet thin-sheet motor according to claim 2, it is characterized in that: the thin slice rotor hard plastic pallet (1) that studs with opening up, a placing sheets rotor (6) between thin slice rotor (6) and Hall element (13) and in the radial air gap (16), thin slice rotor hard plastic pallet (1) sidewall is set on top hard plastic support (8) the inner ring wall, and thin slice rotor hard plastic pallet (1) and thin slice rotor (6) have the gap between radially.

6. a kind of bearing-free permanent magnet thin-sheet motor according to claim 5, it is characterized in that: the wall thickness of thin slice rotor hard plastic pallet (1) is 0.4mm, radial air gap (16) is 2mm.

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