CN104214216B - A four-degree-of-freedom inner rotor magnetic bearing - Google Patents

Abstract

nullA kind of four-degree-of-freedom internal rotor magnetic bearing，By passive part internal rotor magnetic guiding loop、Internal rotor permanent-magnetic body、Internal rotor magnetic conductor、Internal rotor is unshakable in one's determination、Air gap、Stator core、Stator magnetic guiding loop、Stator permanent magnet、Coil、Passive part stator magnetic guiding loop and passive part air gap composition，The most each stator core is made up of 4 magnetic poles，Separately constitute X、The magnetic pole of the positive negative direction of Y-axis，Internal rotor iron core outer surface and stator core inner surface leave certain gap，Form air gap，Two passive part stator magnetic guiding loops are between two stator cores，Two stator permanent magnets are had between stator core and passive part stator magnetic guiding loop，A stator permanent magnet is had between two passive part stator magnetic guiding loops，It is internal rotor permanent-magnetic body between two internal rotor magnetic conductors，Passive part air gap is formed between inner surface and the outer surface of passive part stator magnetic guiding loop of passive part internal rotor magnetic guiding loop，It is little that the present invention has volume、Easy-to-dismount feature.

Description

A four-degree-of-freedom inner rotor magnetic bearing

technical field

The invention relates to a non-contact magnetic suspension bearing, in particular to a four-degree-of-freedom inner rotor magnetic bearing, which can be used as a non-contact support for rotating components such as a single-frame control moment gyroscope and a double-frame control moment gyroscope for space.

Background technique

Magnetic suspension bearings are divided into pure electromagnetic type and hybrid magnetic suspension bearing with permanent magnetic bias and electromagnetic control. The former uses large current and high power consumption, and the hybrid magnetic suspension bearing with permanent magnetic bias and electromagnetic control uses permanent magnets instead of pure electromagnetic magnetic bearings. The bias current in the bearing generates a bias magnetic field, the magnetic field generated by the permanent magnet bears the main bearing capacity, and the electromagnetic field provides an auxiliary adjustment bearing capacity, so this kind of bearing can greatly reduce the control current, reduce the loss of the power amplifier, and reduce the magnetic field. The ampere-turns of the bearing, the reduction of the volume of the magnetic bearing, and the improvement of the bearing capacity, etc., so the permanent magnet bias magnetic bearing has been widely used in the high-speed motion occasions of the magnetic suspension support such as the magnetic levitation motor, high-speed flywheel system, and control torque gyro system. Magnetic levitation control torque gyroscopes for space are supported by magnetic bearings. Because they overcome the problems of friction and unbalanced vibration of traditional mechanical bearing control torque gyroscopes, they can achieve higher speed, longer life and higher output torque accuracy. In order to increase the output torque, the existing magnetic levitation control torque gyroscope usually adopts a five-degree-of-freedom fully active magnetic bearing configuration. However, the magnetic levitation control torque gyroscope with this structure uses current to control the output torque, so it consumes a lot of power and is bulky. , the circuit is complicated, and the two-degree-of-freedom magnetic levitation control torque gyroscope with passive magnetic bearing output torque can be made very small, but because the passive magnetic bearing is uncontrollable, it has the defects of low damping and poor stability. In addition, the existing four The stiffness of the active part of the degree of freedom magnetic bearing and the stiffness of the passive part affect each other, which will increase the control difficulty of the control system.

Contents of the invention

The technical solution of the present invention is to overcome the deficiencies of the prior art and provide a four-degree-of-freedom inner rotor magnetic bearing to reduce its own volume weight and power consumption.

The technical solution of the present invention is: a four-degree-of-freedom inner rotor magnetic bearing, which consists of a passive part inner rotor magnetic ring, an inner rotor permanent magnet, an inner rotor magnetic body, an inner rotor core, an air gap, a stator core, and a stator magnetic Ring, stator permanent magnet, coil, passive part stator magnetic ring and passive part air gap, in which each stator core is composed of 4 magnetic poles, and two stator cores form 8 magnetic poles at the upper and lower ends of the magnetic bearing, which respectively form X, The magnetic poles in the positive and negative directions of the Y-axis, coils are wound on the magnetic poles of each stator core, the interior of the stator core is the inner rotor core, the interior of the inner rotor core is the inner rotor magnetizer, and the outer surface of the inner rotor core and the inner surface of the stator core are left. A certain gap forms an air gap. The radial outer part of the stator core is the stator magnetic ring, and the two passive stator magnetic rings are located between the two stator cores. There are two stator cores and the passive part of the stator magnetic ring. Stator permanent magnet, there is a stator permanent magnet between the two passive stator magnetic rings, the radial inner part of the passive part stator magnetic ring is the passive inner rotor magnetic ring, and the inner rotor is between the two inner rotor magnetic rings For the permanent magnet, there is a certain gap between the outer surface of the inner rotor magnetic ring of the passive part and the inner surface of the stator magnetic ring of the passive part, forming an air gap of the passive part.

The magnetic poles of each stator core are wound with coils for independent control.

The permanent magnets of the inner rotor and each stator permanent magnet are axial rings, magnetized in the axial direction, and have equal volumes.

The magnetic poles of the stator core are in the form of pole shoes.

The inner rotor magnetic conduction ring of the passive part and the stator magnetic conduction ring of the passive part are made of a solid whole ring of magnetic conduction material.

There are two, four, six or eight magnetic conducting rings of the inner rotor of the passive part and magnetic conducting rings of the stator of the passive part.

The reluctance of the air gap in the passive part is 2 to 4 times that of the air gap.

The principle of the above scheme is: the four-degree-of-freedom inner rotor magnetic bearing, by controlling the coils of the upper and lower sets of stator core poles (that is, independently controlling the current in each coil, that is to say, "independent control" refers to the current in each coil There is no direct connection, the power amplifier is used to energize each stator pole coil according to the detected air gap change detected by the displacement sensor), to realize the radial translation and radial torsion of the rotating part of the magnetic bearing, and to use the stator guide in the middle passive part The magnetic ring and the inner rotor magnetic ring of the passive part realize the axial translation of the rotating part of the magnetic bearing through the magnetic bias pulling force generated by the axial displacement. The stator permanent magnet and the inner rotor permanent magnet provide a permanent magnetic bias magnetic field for the magnetic bearing, bear the radial force on the magnetic bearing, and the magnetic field generated by the coil acts as an adjustment function, which is used to change the strength of the magnetic field at each pole and maintain the magnetic field. The air gap between the bearing stator and the rotor is uniform, and the rotor is supported without contact. The permanent magnet magnetic circuit of the present invention is three parts (as shown in Figure 3), and one part is: the magnetic flux starts from the N pole of the upper stator permanent magnet, passes through the stator magnetic ring, the upper stator core, the upper air gap, and the upper inner rotor Iron core, upper inner rotor magnetizer, upper passive part inner rotor magnetic ring, upper passive part air gap, upper passive part stator magnetic ring, stator magnetic ring returns to the S pole of the upper stator permanent magnet; the second part is: The magnetic flux starts from the N pole of the lower stator permanent magnet, and passes through the stator magnetic ring, the lower passive part of the stator magnetic ring, the lower passive part air gap, the lower passive part inner rotor magnetic ring, the lower inner rotor magnetic body, and the lower inner rotor core , the air gap at the lower end, the lower stator core, and the stator magnetic ring return to the S pole of the lower stator permanent magnet; the third part is: the magnetic flux starts from the N pole of the stator permanent magnet in the middle, passes through the stator magnetic ring, and the lower passive part of the stator Magnetic ring, lower passive part air gap, lower passive inner rotor magnetic ring, lower inner rotor magnetic conductor, inner rotor permanent magnet S pole, inner rotor permanent magnet N pole, upper inner rotor magnetic conductor, upper passive inner rotor The magnetic ring, the air gap of the upper passive part, the stator magnetic ring of the upper passive part, and the stator magnetic ring return to the S pole of the permanent magnet of the middle stator. As shown in Figure 2, taking the magnetic flux generated by the coil current in the positive direction of the Y-axis at one end as an example, its path is: the magnetic pole in the positive direction of the Y-axis formed by the stator core, the air gap in the positive direction of the Y-axis to the inner rotor core, and then to the other side. Air gaps in three directions, magnetic poles in the other three directions formed by the stator core, and magnetic poles in the positive direction of the Y axis formed by returning to the stator core form a closed loop.

Compared with the prior art, the present invention has the advantages that: the present invention utilizes the stator core to provide four-degree-of-freedom radial force and gyro torque, high control precision, passive realization of the axial translational degree of freedom, low power consumption, and small volume; Each stator permanent magnet of the present invention has the same volume as the inner rotor permanent magnet, which can make the residual magnetic moment of the magnetic bearing close to zero and meet the requirements of aerospace; the inner rotor permanent magnet of the present invention is only used to increase the passive stiffness of the axial translation, It has no influence on the core part of the stator, so that the active part has little influence on the rigidity of the passive part; in addition, the axial passive part of the present invention is a complete ring structure, with small magnetic field fluctuation and low rotational power consumption.

Description of drawings

Fig. 1 is an axial sectional view of a four-degree-of-freedom inner rotor magnetic bearing of the present invention;

Fig. 2 is an axial end view of a four-degree-of-freedom inner rotor magnetic bearing of the present invention; wherein Fig. 2a is an end view in the form of a pole shoe, and Fig. 2b is an end view when the angle between the stator magnetic poles is 62 degrees;

Fig. 3 is the permanent magnet magnetic circuit diagram of the four-degree-of-freedom inner rotor magnetic bearing of the present invention;

Fig. 4 is an axial cross-sectional view of a four-degree-of-freedom inner rotor magnetic bearing containing four passive part inner rotor magnetic conduction rings and a passive part stator magnetic conduction ring according to the present invention.

detailed description

As shown in Figure 1, a four-degree-of-freedom inner rotor magnetic bearing consists of a passive part inner rotor magnetic ring 1, an inner rotor permanent magnet 2, an inner rotor magnet 3, an inner rotor core 4, an air gap 5, and a stator core 6 , stator magnetic ring 7, stator permanent magnet 8, coil 9, passive part stator magnetic ring 10 and passive part air gap 11, wherein each stator core 6 is composed of 4 magnetic poles, and two stator cores 6 form a magnetic bearing There are 8 magnetic poles at the upper and lower ends, which respectively form the magnetic poles in the positive and negative directions of the X and Y axes. A coil 9 is wound on each magnetic pole of the stator core 6. The inside of the stator core 6 is the inner rotor core 4, and the inner rotor core 4 is the inner rotor core. The rotor magnetizer 3, the outer surface of the inner rotor core 4 and the inner surface of the stator core 6 leave a certain gap to form an air gap 5, the radial outer part of the stator core 6 is the stator magnetic ring 7, and the two passive parts of the stator magnetic ring 10 is located between the two stator cores 6, there are two stator permanent magnets 8 between the stator core 6 and the passive part of the stator magnetic ring 10, and there is a stator permanent magnet 8 between the two passive part stator magnetic rings 10. The radial inner part of the stator magnetic ring 10 is the passive part inner rotor magnetic ring 1, the inner rotor permanent magnet 2 is between the two inner rotor magnetic bodies 3, the outer surface of the passive part inner rotor magnetic ring 1 and the passive part A certain gap is left between the inner surfaces of the stator magnetic permeable rings 10 to form an air gap 11 in the passive part.

The magnetic poles of each stator core 6 are wound with coils 9 for independent control, so as to realize the radial translation control and radial torsion control of the rotating part of the magnetic bearing, that is, to realize the two rotations of the rotating part of the magnetic bearing along the x and y directions. Translational degree of freedom control and two torsional degrees of freedom around the x and y directions (four degrees of freedom in total).

The inner rotor magnetic ring 1 of the passive part and the stator magnetic ring 10 of the passive part are made of a solid whole ring magnetic material, through the axial misalignment of the inner rotor magnetic ring 1 of the passive part and the stator magnetic ring 10 of the passive part Realize the axial stability of the magnetic bearing (that is, the axial translation degree of freedom is passive).

In order to increase the rigidity of the passive part, there are two, four, six or eight inner rotor magnetic rings 1 of the passive part and stator magnetic rings 10 of the passive part. The magnetic ring and the passive part of the stator magnetic ring are four cross-sectional views of the inner rotor four-degree-of-freedom magnetic bearing.

In addition, in order to reduce the additional displacement negative stiffness brought by the passive part to the active part, the magnetic resistance of the air gap 11 of the passive part is 2 to 4 times that of the air gap 5 .

The passive part of the inner rotor magnetic ring 1, the inner rotor magnetic body 3, the stator magnetic ring 7 and the passive part of the stator magnetic ring 10 used in the technical solution of the present invention are all solid structures, and are made of materials with good magnetic properties. Such as electrical pure iron, various carbon steel, cast iron, cast steel, alloy steel, 1J50 and 1J79 and other magnetic materials. The stator core 6 and the inner rotor core 4 can be formed by stamping and stacking magnetic materials such as electrical pure iron, electrical silicon steel plates DR510, DR470, DW350, 1J50 and 1J79 with good magnetic permeability. The materials of the inner rotor permanent magnet 2 and the stator permanent magnet 8 are rare earth permanent magnets, neodymium iron boron permanent magnets or ferrite permanent magnets with good magnetic properties, and the inner rotor permanent magnet 2 and the stator permanent magnet 8 are axial rings, along the Axial magnetization, and the inner rotor permanent magnet 2 and each stator permanent magnet 8 must ensure that the volume is equal, and the magnetization direction of each adjacent two stator permanent magnets 8 must be opposite, the stator between the passive part of the stator magnetic ring The magnetization direction of the permanent magnet 8 is opposite to the magnetization direction of the inner rotor permanent magnet 2 between the inner rotor magnetic rings of the passive part. The coil 9 is formed by winding an electromagnetic wire with good electrical conductivity, dipping in paint and drying. In addition, since the magnetic field generated by the permanent magnets changes in size through the magnetic poles of the stator core, the magnetic field generated in the inner rotor core changes, so eddy current losses will occur when the rotor rotates at high speed. In order to reduce this part of the loss, the magnetic poles of the stator core 6 should use The pole shoe form (as shown in Figure 2a) is used to reduce the eddy current loss at high speed. In addition, in order to reduce the problem of excessive magnetic density caused by the acute angle between the stator core magnetic pole root and the stator core yoke in Figure 2a, The end view of the stator core shown in Figure 2b can be used. The central angle corresponding to the two sides of the stator core pole shown in the figure is 62 degrees. This structure can effectively reduce the acute angle between the root of the stator core pole and the stator core yoke. The resulting magnetic density.

The contents not described in detail in the description of the present invention belong to the prior art known to those skilled in the art.

Claims (7)

1. A four-degree-of-freedom inner rotor magnetic bearing, characterized in that: the inner rotor magnetic ring (1), the inner rotor permanent magnet (2), the inner rotor magnetizer (3), the inner rotor core (4) , air gap (5), stator core (6), stator magnetic ring (7), stator permanent magnet (8), coil (9), passive stator magnetic ring (10) and passive air gap (11) Each stator core (6) is composed of 4 magnetic poles, and two stator cores (6) form 8 magnetic poles at the upper and lower ends of the magnetic bearing, which respectively form the magnetic poles in the positive and negative directions of the X and Y axes. Each stator core ( Coils (9) are wound on the magnetic poles of 6), the inside of the stator core (6) is the inner rotor core (4), the inside of the inner rotor core (4) is the inner rotor magnetizer (3), and the inner rotor core (4) is There is a certain gap between the surface and the inner surface of the stator core (6), forming an air gap (5), the radially outer part of the stator core (6) is the stator magnetic ring (7), and the two passive stator magnetic rings (10 ) between the two stator cores (6), there are two stator permanent magnets (8) between the stator core (6) and the passive part of the stator magnetic ring (10), and the two passive part of the stator magnetic ring (10) There is also a stator permanent magnet (8) between them, the radial inner part of the passive part of the stator magnetic conducting ring (10) is the passive part of the inner rotor magnetic conducting ring (1), and between the two inner rotor magnetic conducting bodies (3) is an inner The rotor permanent magnet (2), a certain gap is left between the outer surface of the inner rotor magnetic conducting ring (1) of the passive part and the inner surface of the stator magnetic conducting ring (10) of the passive part, forming an air gap (11) of the passive part. 2. The four-degree-of-freedom inner rotor magnetic bearing according to claim 1, characterized in that: the magnetic poles of each stator core (6) are wound with coils (9) for independent control. 3. The four-degree-of-freedom inner rotor magnetic bearing according to claim 1, characterized in that: the inner rotor permanent magnet (2) and each stator permanent magnet (8) are axial circular rings, filled axially Magnetic and equal in size. 4. The four-degree-of-freedom inner rotor magnetic bearing according to claim 1, characterized in that: the magnetic poles of the stator core (6) are in the form of pole shoes. 5. The four-degree-of-freedom inner rotor magnetic bearing according to claim 1, characterized in that: the inner rotor magnetic ring (1) of the passive part and the stator magnetic ring (10) of the passive part are magnetically conductive by a solid whole ring material. 6. The four-degree-of-freedom inner rotor magnetic bearing according to claim 1, characterized in that: the inner rotor magnetic ring (1) of the passive part and the stator magnetic ring (10) of the passive part are two or four , six or eight. 7. The four-degree-of-freedom inner rotor magnetic bearing according to claim 1, characterized in that: the reluctance of the air gap (11) of the passive part is 2 to 4 times of the reluctance of the air gap (5).