CN107294323A - A kind of axial permanent magnetic auxiliary reluctance motor and its control method - Google Patents

Abstract

An axial permanent magnet assisted reluctance motor and its control method, belonging to the technical field of direct current motors; the motor includes: two sets of stators, two sets of rotors, a permanent magnet fixed in the center of the rotating shaft, and a wedge-shaped The two sets of rotors are fixed on the wedge-shaped slots, the two sets of stators are respectively arranged outside the two sets of rotors, the two sets of stators are fixed outside the casing, there are 9 salient poles on each set of stators, and 6 salient poles on each set of rotors. The two sets of stators are divided into three phases A, B, and C; the method includes: starting the motor with a difference of 22.5° between the center line of the stator teeth of the A phase and the center line of the rotor teeth; electrifying the winding of the A phase, and when the rotor rotates 20°, the A phase The winding is de-energized, and the B-phase winding is energized. When the rotor rotates 20°, the B-phase winding is de-energized, and the C-phase winding is energized, and the cycle is repeated in turn; the invention reduces the torque ripple; adding permanent magnets increases the stability of the motor, Improve the performance of the motor; enhance the magnetic performance of the motor, and reduce the moment of inertia.

Description

An axial permanent magnet assisted reluctance motor and its control method

technical field

The invention belongs to the technical field of DC motors, in particular to an axial permanent magnet assisted reluctance motor and a control method thereof.

Background technique

Switched reluctance motor is the most common reluctance motor, because of its solid structure, simple, low cost, large starting torque, good speed regulation performance, strong fault tolerance and flexible control methods, it has been increasingly used in the industrial field. Wide range of applications. With the development and application of materials, power electronics technology, digital control technology, control theory and sensor technology, on the basis of switched reluctance motor, double salient pole motor has become a new type of special motor developed in recent years. Its control The technology has become more and more mature. At present, it has been widely used in the fields of rail transit, lathes, aerospace, automobiles, household appliances and industrial process control. However, switched reluctance motors have their disadvantages: From the perspective of energy conversion, switched reluctance motors only obtain half of the utilization rate, low power density, large instantaneous torque ripple and a certain degree of magnetic flux leakage that lead to their operating efficiency Low.

Contents of the invention

Aiming at the deficiencies in the above-mentioned prior art, the present invention provides an axial permanent magnet assisted reluctance motor and its control method, adopting a new angle control method to enable the motor to increase output torque, reduce torque ripple, and add permanent The magnet increases the power per unit volume and expands the range of use of the motor.

Technical scheme of the present invention:

An axial permanent magnet assisted reluctance motor, comprising two sets of stators, two sets of rotors, a rotating shaft, wedge-shaped slots, permanent magnets and a casing; the permanent magnet is in the shape of a round pie, coaxial with the rotating shaft and fixed in the center of the rotating shaft, Both sides of the permanent magnet are provided with wedge-shaped grooves wrapped around the surface of the rotating shaft. The wedge-shaped grooves are made of magnetically permeable materials and fixed with the rotating shaft; the stator and the rotor are both laminated with silicon steel sheets. The two sets of rotors are respectively It is fixed on the wedge-shaped grooves on both sides of the permanent magnet, and the two sets of stators are respectively arranged outside the two sets of rotors, and there is an air gap between the stators and the rotors to form a pair of stator and rotor sets, which are symmetrical on both sides of the permanent magnets, and There is a certain space between the permanent magnet and the casing, which is arranged outside the two sets of stators and fixed with the two sets of stators.

There are 9 salient poles or stator teeth on each set of stators, and 6 salient poles or rotor teeth on each set of rotors, and windings are wound on each stator tooth; the stator pole arc is 20°, and the rotor pole arc is 15°; two sets of stators are divided into three phases A, B, and C that are symmetrical to the permanent magnets. Among them, the symmetrical A-phase windings on both sides of the permanent magnets are connected in series to form a phase, and the symmetrical B-phase windings on both sides of the permanent magnets are connected in series to form a phase. The symmetrical C-phase windings on both sides of the magnet are connected in series to form a phase.

The control method of the axial permanent magnet assisted reluctance motor includes the following steps:

Step 1: When the motor is started, make the phase A stator tooth centerline and rotor tooth centerline differ by 22.5°;

Step 2: A phase winding is energized to generate tangential pulling force to drive the rotor to rotate;

Step 3: When the rotor rotates through 20°, the A-phase winding is de-energized, and the B-phase winding is energized to generate a tangential pulling force to drive the rotor to rotate;

Step 4: When the rotor rotates another 20°, the B-phase winding is de-energized, and the C-phase winding is energized;

Step 5: When the rotor rotates another 20°, the phase C winding is de-energized, repeat step 2, and the motor runs continuously.

The conduction angle of each phase of the motor is 20°, realizing continuous commutation, reducing torque ripple and improving the stability of the motor.

Beneficial effects: Compared with the prior art, an axial permanent magnet assisted reluctance motor and its control method of the present invention have the following advantages:

(1) The use of a salient-pole stator-rotor structure and a new conduction method reduces torque ripple;

(2) Permanent magnets are added between the two sets of stators and rotors to increase the stability of the motor and improve the performance of the motor;

(3) Both the stator and the rotor are made of laminated silicon steel sheets, and there are wedge-shaped grooves made of magnetically conductive materials on the rotating shaft, which enhance the magnetically conductive performance of the motor and reduce the moment of inertia.

Description of drawings

Fig. 1 is a left view of an axial permanent magnet assisted reluctance motor according to an embodiment of the present invention;

Fig. 2 is a three-dimensional structural schematic diagram of an axial permanent magnet assisted reluctance motor according to an embodiment of the present invention;

Fig. 3 is a front view of an axial permanent magnet assisted reluctance motor according to an embodiment of the present invention;

Fig. 4 is a partial schematic diagram of an axial permanent magnet assisted reluctance motor according to an embodiment of the present invention;

Fig. 5 is a starting position diagram of an axial permanent magnet assisted reluctance motor according to an embodiment of the present invention;

Among them, 1-stator, 2-rotor, 3-rotating shaft, 4-wedge slot, 5-permanent magnet, 6-casing, 7-stator tooth, 7A-phase A stator tooth, 7B-phase B stator tooth, 8, 8a, 8b-rotor teeth, 9-winding;

Fig. 6 is a flowchart of an axial permanent magnet assisted reluctance motor control method according to an embodiment of the present invention;

Fig. 7 is a position diagram of an axial permanent magnet assisted reluctance motor at start-up time according to an embodiment of the present invention;

Fig. 8 is a position diagram of the commutation time of an axial permanent magnet assisted reluctance motor according to an embodiment of the present invention.

detailed description

An embodiment of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figures 1-3, an axial permanent magnet assisted reluctance motor in this embodiment includes two sets of stators 1, two sets of rotors 2, a rotating shaft 3, wedge slots 4, permanent magnets 5 and a housing 6; The permanent magnet 5 is round cake-shaped, coaxial with the rotating shaft 3 and fixed in the center of the rotating shaft 3, and the two sides of the permanent magnet 5 are provided with wedge-shaped grooves 4 wrapped around the outside of the rotating shaft, and the wedge-shaped groove 4 is made of a magnetically conductive material and It is fixed with the rotating shaft; in this embodiment, as shown in FIG. 4 , the wedge-shaped slot 4 is in the shape of a truncated cone near the permanent magnet, and extends outward in a cylindrical shape.

Both the stator 1 and the rotor 2 are made of laminated silicon steel sheets, the two sets of rotors 2 are fixed on the wedge-shaped groove cylindrical parts of the shafts on both sides of the permanent magnet 5, and the two sets of stators 1 are respectively arranged on the two sets of rotors 2 outside, and there is an air gap between the stator 1 and the rotor 2 to form a pair of stator and rotor groups. The stator and rotor groups on both sides of the permanent magnet are symmetrical. The casing 6 is arranged outside the two sets of stators and is fixed with the two sets of stators 1 .

There are 9 salient poles on each group of stators, that is, stator teeth 7, and each group of rotors has 6 salient poles, that is, rotor teeth 8, and windings 9 are wound on each stator tooth; the stator pole arc is 20°, and the rotor The pole arc is 15°; as shown in Figure 5, the two sets of stators are divided into three phases A, B, and C that are symmetrical to the permanent magnets, and the three stator teeth adjacent to the stator set are A phase, B phase, and C phase. Among them, the symmetrical A-phase excitation windings on both sides of the permanent magnet are connected in series to form a phase, the symmetrical B-phase excitation windings on both sides of the permanent magnet are connected in series to form a phase, and the symmetrical C-phase excitation windings on both sides of the permanent magnet are connected in series to form a phase.

The permanent magnet establishes a constant axial magnetic field, and the two ends of the motor form N poles and S poles. By controlling the conduction sequence of the windings, the motor rotates. The windings at both ends are energized to form the same axial magnetic flux as the permanent magnet, which is transmitted through the rotating shaft, from the rotor on one side of the permanent magnet through the stator, from the motor casing to the stator on the other side of the permanent magnet, and returns to the rotating shaft through the rotor to form a closed magnetic circuit . The magnetic field of the permanent magnet and the magnetic field formed by the electrification of the winding are superimposed to increase the power density, increase the torque of the motor, and expand the speed regulation range of the motor.

As shown in Figure 6, the control method of the axial permanent magnet assisted reluctance motor includes the following steps:

Step 1: The stator pole arc of the motor is 20°, and the rotor pole arc is 15°. When the motor is started, in order to obtain a larger starting torque and a faster starting speed, as shown in Figure 7, the center of the phase A stator tooth 7A The position where the difference between the line and the center line of the rotor tooth 8a is 22.5° is the position when starting;

Step 2: A phase winding is energized to generate tangential pulling force to drive the rotor to rotate;

Step 3: When the rotor rotates through 20°, as shown in Figure 8, the rotor tooth 8a overlaps with the phase A stator tooth 7A by 15°, and the difference between the center line of the rotor tooth 8a and the B phase stator tooth 7B is 32.5°, and the rotor tooth The difference between the 8b center line and the 7B center line of the B-phase stator tooth is 27.5°. The A-phase winding is powered off and continues to flow. There will be no current generation in the inductance drop zone, which prevents the generation of negative torque. The B-phase winding is energized, resulting in cutting The pulling force drives the rotor to rotate;

Step 4: When the rotor rotates through 20°, the B-phase winding is de-energized, and the C-phase winding is energized;

Step 5: When the rotor turns 20°, the phase C winding is powered off, repeat step 2, and the motor runs continuously.

The conduction angle of each phase of the motor is 20°, realizing continuous commutation, reducing torque ripple and improving the stability of the motor.

Claims (6)

1. An axial permanent magnet assisted reluctance motor, characterized in that, comprising: Two sets of stators, two sets of rotors, rotating shafts, permanent magnets and casings; the permanent magnets are fixed in the center of the rotating shaft, the two sets of rotors are respectively fixed on the rotating shafts on both sides of the permanent magnets, and the two sets of stators are respectively arranged in two sets of The rotor is outside, and there is an air gap between the stator and the rotor to form a pair of stator and rotor groups. The casing is arranged outside the two groups of stators and fixed with the two groups of stators; There are 9 salient poles or stator teeth on each set of stators, and 6 salient poles or rotor teeth on each set of rotors, and windings are wound on each stator tooth; the two sets of stators are divided into Symmetrical A, B, C three-phase, in which, the symmetrical A-phase windings on both sides of the permanent magnet are connected in series to form a phase, the symmetrical B-phase windings on both sides of the permanent magnet are connected in series to form a phase, and the symmetrical C-phase windings on both sides of the permanent magnet are connected in series to form a phase . 2 . The axial permanent magnet assisted reluctance motor according to claim 1 , wherein the stator and the rotor are both made of laminated silicon steel sheets. 3 . The axial permanent magnet assisted reluctance motor according to claim 1 , wherein the stator and rotor groups on both sides of the permanent magnet are arranged symmetrically with respect to the permanent magnet, and there is a certain space between the permanent magnet and the permanent magnet. 4 . 4. The axial permanent magnet assisted reluctance motor according to claim 1, characterized in that, the stator pole arc is 20°, and the rotor pole arc is 15°. 5. The axial permanent magnet assisted reluctance motor according to claim 1, characterized in that, the permanent magnet is in the shape of a round cake, coaxially fixed to the center of the rotating shaft, and the two sides of the permanent magnet are provided with The wedge-shaped slots on the surface, the two groups of rotors are respectively fixed on the wedge-shaped slots on both sides of the permanent magnet, and the wedge-shaped slots are made of magnetically permeable materials. 6. The control method of the axial permanent magnet assisted reluctance motor according to claim 1, characterized in that, comprising the steps of: Step 1: When the motor is started, make the phase A stator tooth centerline and rotor tooth centerline differ by 22.5°; Step 2: A phase winding is energized to generate tangential pulling force to drive the rotor to rotate; Step 3: When the rotor rotates through 20°, the A-phase winding is de-energized, the B-phase winding is energized, and the rotor continues to rotate under the action of tangential tension; Step 4: When the rotor rotates another 20°, the B-phase winding is de-energized, and the C-phase winding is energized; Step 5: When the rotor rotates another 20°, the phase C winding is de-energized, repeat step 2, and the motor runs continuously.