CN101207310B - Three-freedom consequent pole permanent magnet motor without bearing of axial direction initiative suspending - Google Patents

Abstract

The invention relates to an axial initiative-suspension three-dimensional bearing-free alternative-pole permanent-magnetic machine, which belongs to a bearing-free magnetic-suspension motor. The machine comprises two axial stator cores (1) that are provided with axial suspension controlling windings (8) that are serially connected with each other, a radial stator core (2) that is provided with a set of four-pair-pole torque controlling windings (7) and a set of one-pair-pole radial suspension controlling windings (6), a rotor core (4) that is provided with four homo-polar magnetizing permanent-magnets (3) and a rotor rotating shaft (5) that is enclosed with the rotor core (4). The motor has simple and compact structure, is free from additional axial magnetic bearing, integrates the motor rotation and axial and radial simultaneous-suspension functions of the rotor, has high integration, enlarges the suspension freedom of the bearing-free motor, simplifies the system structure, reduces the volume, the weight and the cost of the system, and has broad application prospect and important significance in different high-speed magnetic-suspension motor systems.

Description

A three-degree-of-freedom bearingless alternating-pole permanent magnet motor with active axial suspension

1. Technical field

The invention is a three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension, which is suitable for many special power transmission fields such as high-speed and ultra-high-speed spindle motors, aerospace, life science, chemical industry, semiconductor industry, etc. Contact, no friction and wear, vacuum technology without lubrication and sealing, ultra-clean fields and other occasions, belong to the magnetic levitation motor using bearingless technology.

2. Background technology

Traditional three-degree-of-freedom maglev systems usually have four structures:

1. It is composed of an axial magnetic bearing and a two-degree-of-freedom radial magnetic bearing;

2. It is composed of an axial magnetic bearing and a two-degree-of-freedom bearingless motor;

3. It is composed of a two-degree-of-freedom bearingless sheet motor;

4. It is composed of an integrated three-degree-of-freedom permanent magnetic bias axial-radial hybrid magnetic bearing.

Among them, due to the complex mechanical structure of the motor in the first and second structures, the axial suspension needs to occupy a certain axial space, and the axial length of the rotor is relatively long, which is not conducive to increasing the critical speed of the motor; the axial suspension of the third structure relies on Passive suspension cannot be actively controlled, and it is prone to instability under high-speed and load conditions; although the fourth structure integrates the axial and radial suspension into one body and shortens the axial length of the rotor, it still only has suspension support when used alone function and cannot realize torque output.

The two-degree-of-freedom alternating pole permanent magnet motor using bearingless technology solves the problem of poor magnetic control ability of traditional bearingless permanent magnet synchronous motor from the perspective of the motor body, the controllable levitation force is small, the permanent magnet is easy to demagnetize, and the levitation force and torque Problems such as control mutual coupling have promoted the application and development of two-degree-of-freedom permanent magnet bearingless motors. In order to further simplify the mechanical structure of the motor system, reduce the volume and cost of the entire system, and realize the high-speed rotation and suspension control of the three-degree-of-freedom motor from the perspective of the motor body, it is necessary to have a more compact structure, and more concentrated multi-degree-of-freedom suspension functions and motor rotation functions new motors.

At present, there is no concept of "three-degree-of-freedom bearingless motor" at home and abroad, and there are no related patents and documents.

3. Contents of the invention

The purpose of the present invention is to change the old structure of the traditional bearingless motor which can only control two degrees of freedom in the radial direction, and design a simple and compact structure with more perfect functions, high power density, large bearing capacity, small volume, light weight and reliability High performance three-degree-of-freedom active suspension bearingless motor.

The three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension to achieve the above purpose includes a radial stator core, a rotor permanent magnet, a rotor core, and a rotor shaft, and is characterized in that it also includes two axial stator cores installed on radial To the left and right ends of the stator core, a set of axial suspension control windings are respectively embedded and wound on the two axial stator cores, and the two sets of axial suspension control windings are connected in series. The radial stator core (2) is respectively embedded with a set of three-phase four-pole torque control windings for controlling the torque output of the motor and a set of three-phase one-to-one windings for controlling the radial suspension force on the rotor core. Pole radial suspension control windings, the rotor permanent magnets are installed on the outer circumference of the rotor core in the radial direction, the rotor permanent magnets are arranged with the same polarity in the radial direction, and the rotor core between the rotor permanent magnets is alternately magnetized The other polarity is the same, and the rotor core with the rotor shaft is placed in the middle of the radial stator core.

The working principle of the present invention is: for the two-degree-of-freedom levitation in the radial direction, the radial displacement offset of the rotor is detected by the radial displacement sensor. The corresponding levitation control current is input to change the symmetrical distribution of the motor's rotating magnetic field, thereby generating a radial levitation force with controllable magnitude and direction on the rotor, and realizing the two-degree-of-freedom levitation of the motor in the radial direction. For the levitation in the axial direction, when the rotor is in the middle balance position in the axial direction, due to the symmetry of the rotor structure, the magnetic fields of the same polarity generated by the permanent magnets of the rotor are equal at the left and right sides of the air gap in the axial direction of the rotor. The resulting magnetic pull forces balance each other. If the rotor is subjected to an axial rightward external disturbance at this time, the rotor will deviate from the equilibrium position and move to the right, causing the magnetic field generated by the rotor permanent magnet at the axial left and right air gaps to change, that is, the left air gap increases, and the magnetic field decrease; the air gap on the right side decreases, and the magnetic field increases, so that the magnetic pull on the left and right sides is no longer balanced. At this time, the axial displacement sensor detects the displacement of the axial deviation of the rotor, and the current is passed through the axial control winding to generate an axial control magnetic field. The magnetic field in the gap increases and the magnetic field in the air gap on the right decreases, creating a magnetic pull to the left that pulls the rotor back to its equilibrium position.

The three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension of the present invention has the following characteristics:

1. The alternating pole bearingless permanent magnet motor used in radial suspension is easy to control the magnetism, there is no contradiction between the torque and suspension force of ordinary bearingless permanent magnet motors, the suspension current is small, and the carrying capacity and stiffness are doubled;

2. Axial suspension adopts permanent magnet bias, which reduces the volume and power consumption of the power amplifier, and reduces the manufacturing cost;

3. The rotor body of the motor is used as the closed path of the axial and radial suspension flux linkages, and the permanent magnet magnetic field of the motor rotor itself is used as the common bias magnetic field for radial and axial suspension, eliminating the need for the original permanent magnet bias axial magnetic field. The necessary magnetic bearing rotor and offset permanent magnet ring in the bearing simplifies the system structure, reduces the consumption of permanent magnets, and reduces the volume and weight of the system;

4. The structure of the motor is simple and compact, with high integration, which further shortens the space occupied by the axial direction, improves the utilization rate of the axial space, has a high critical speed, and is easy to realize high-power ultra-high-speed operation;

5. With the inherent decoupling characteristics of radial suspension and axial suspension, suspension control and torque control decoupling, the suspension control model is simple, which greatly reduces the difficulty of control system design;

6. The axial suspension function is integrated into the bearingless motor itself, which is convenient for modularization and machining.

In short, the three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension of the present invention organically combines the respective advantages of the bearingless technology and the axial magnetic bearing technology, and cleverly utilizes the rotor of the bearingless alternating pole permanent magnet motor The magnetic field generated by the magnet is used as the common bias magnetic field for the axial and radial suspension of the motor, and forms a closed magnetic circuit through the radial stator, rotor core and axial stator respectively, without changing the original two-degree-of-freedom bearingless alternating pole permanent magnet On the basis of the motor structure, the axial suspension function is integrated into the motor body without additional axial magnetic bearings, so that the motor rotation and rotor axial and radial suspension functions are integrated, breaking through the traditional bearingless motor only The old theoretical framework that can realize radial two-degree-of-freedom levitation expands the degree of freedom of bearingless motor levitation, develops a new direction in the field of bearingless motor research, and has broad application prospects and important importance in various magnetic levitation motor systems. significance.

4. Description of drawings

Fig. 1 is a schematic diagram of the two-dimensional structure of a three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension. The left figure in the figure is a cross-sectional view of a three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension, and the right figure is a right view of the left figure.

Fig. 2 is a three-dimensional structural schematic diagram of a three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension. The left figure in the figure is a schematic diagram of the stator and rotor structure, and the right figure is a schematic diagram of the winding structure.

Fig. 3 is a schematic diagram of a three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension. The left picture in the figure is a schematic diagram of the principle of axial suspension, and the right picture is a schematic diagram of the principle of radial suspension.

Label name: 1: axial stator core; 2: radial stator core; 3: rotor permanent magnet; 4: rotor core; 5: rotor shaft; 6: radial suspension control winding; 7: torque control winding; 8: Axial suspension control winding. A, C are axial air gaps, B, D, E are radial air gaps, single arrows indicate permanent magnet bias flux, double solid arrows indicate magnetic flux generated by axial control windings, double hollow arrows indicate radial control The magnetic flux produced by the winding.

5. Specific implementation

Fig. 1 and Fig. 2 are two-dimensional and three-dimensional schematic diagrams of the three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension of the present invention, which mainly consists of an axial stator core 1, a radial stator core 2, and a rotor permanent magnet 3 , rotor core 4, rotor shaft 5 components. Among them, two axial stator cores 1 are processed by electrical pure iron, and are respectively installed on the left and right ends of the radial stator core 2. A set of axial suspension control windings 8 are respectively embedded and wound on the two axial stator cores 1. Two sets of axial suspension control windings 8 are connected in series. Both the radial stator core 2 and the rotor core 4 are made of laminated silicon steel sheets, and a set of three-phase four-pole torque control winding 7 for controlling the torque output of the motor is embedded and wound on the radial stator core 2, and a set for The three-phase one-pole radial suspension control winding 6 that controls the radial suspension force on the rotor 4 . The rotor permanent magnets 3 installed on the rotor core 4 are arranged with the same polarity in the radial direction, and the rotor core 4 between the rotor permanent magnets 3 is alternately magnetized into the same other polarity. The rotor core 4 is placed in the middle of the radial stator core 2 .

Fig. 3 is a schematic diagram of the axial and radial suspension of the three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension. The axial bias flux generated by the rotor permanent magnet 3 passes through the radial air gap B, the radial stator core 2, the axial stator core 1, the axial air gap A (or air gap C), and the rotor core as shown in the figure. 4 forms a loop, and the control magnetic flux generated by the axial suspension control winding 8 only passes through the axial air gap A (or air gap C), and does not pass through the radial air gap B (or air gaps D, E). The axial control magnetic flux is superimposed on the permanent magnet bias flux, so that the magnetic fields of the axial air gaps A and C are weakened on one side and strengthened on the other side, thereby generating an axially controllable levitation force to keep the rotating shaft 5 axially levitated . The radial bias magnetic flux generated by the rotor permanent magnet 3 passes through the radial air gap B, the radial stator core 2, the radial air gap D (or air gap E), and the rotor core 4 to form a loop as shown in the figure. The control magnetic flux generated by the radial suspension control winding 6 only passes through the axial air gap D (or air gap E), and does not pass through the axial air gap B (or air gap C). The principle of magnetic field superposition can also generate a radially controllable levitation force to realize the radial levitation of the rotating shaft 5 .

Claims (1)

1. A three-degree-of-freedom bearingless alternating pole permanent magnet motor with axial active suspension, comprising a radial stator core (2), a rotor permanent magnet (3), a rotor core (4), and a rotor shaft (5), its characteristics It also includes two axial stator cores (1) installed on the left and right ends of the radial stator core (2), and a set of axial suspension control windings ( 8), two sets of axial suspension control windings (8) are connected in series, and a set of three-phase four-pole pair torque control windings ( 7) and a set of three-phase one-pole radial suspension control windings (6) for controlling the radial suspension force on the rotor core (4), the rotor permanent magnet (3) is installed on the rotor core in a radial direction (4) On the outer circumference, the rotor permanent magnets (3) are arranged with the same polarity in the radial direction, and the rotor core (4) between the rotor permanent magnets (3) is alternately magnetized into the same polarity, and the The rotor core (4) with the rotor shaft (5) is placed in the middle of the radial stator core (2).

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