CN107181382B - Rotor stagger angle stator magnetism-isolating type axial permanent magnet auxiliary doubly salient motor - Google Patents

Abstract

A staggered rotor and stator magnetic isolation type axial permanent magnet auxiliary double salient motor, belonging to the field of double salient reluctance motors; including: two sets of magnetic isolation stators, two sets of circumferential staggered rotors, a rotating shaft, a casing, Axial ring-type composite permanent magnets, magnetic conductive strips and field windings. The axial ring-type composite permanent magnets are ring-enclosed in the center of the rotating shaft. Two sets of circumferential staggered angle rotors are fixed on both sides of the shaft. On the top, the magnetically isolated stator includes a partitioned stator yoke and salient poles; each salient stage is wound with an excitation winding; the magnetically isolated stator is set correspondingly to the circumferentially staggered rotor, and has an air gap; the casing is coaxial with the rotating shaft , six magnetic isolation strips are arranged on the inner wall of the casing. The magnetic isolation stator is fixed in the magnetic isolation groove of the casing. The magnetic conductive strips are used to connect the stator yokes on both sides to act as a magnetic bridge. This invention can effectively increase the output torque. Under certain conditions, the armature current is reduced, the motor torque ripple is improved, and the stator yoke loss is reduced, thereby increasing the motor operating efficiency and improving the motor performance indicators.

Description

A rotor staggered stator magnetic isolation axial permanent magnet auxiliary double salient pole motor

Technical field

The invention belongs to the field of doubly salient reluctance motors, and specifically relates to a rotor staggered angle stator magnet isolation type axial permanent magnet auxiliary doubly salient motor.

Background technique

As the most commonly used doubly salient motor, switched reluctance motors are developing rapidly. The drive circuit of switched reluctance motors is simple and can maintain efficient operation in a wide speed range. However, the torque pulsation of ordinary convex reluctance motors Larger, the magnetic flux loss in the yoke between adjacent stator teeth is larger and energy is wasted.

Contents of the invention

In view of the shortcomings of the above-mentioned existing technologies, the present invention provides a rotor staggered stator magnetic isolation type axial permanent magnet auxiliary double salient pole motor, which can effectively increase the output torque and reduce the armature current under certain conditions. , improve the torque ripple of the motor and reduce the loss of the stator yoke, thereby improving the operating efficiency of the motor and improving the performance indicators of the motor;

Technical solution of the present invention:

A rotor staggered stator magnetic isolation type axial permanent magnet auxiliary double salient pole motor, including:

Two sets of magnetically isolated stators, two sets of circumferentially staggered rotors, rotating shafts, casings, axial ring-type composite permanent magnets, magnetic conductive strips and excitation windings;

The axial ring-type composite permanent magnet includes a permanent magnet and a magnetically conductive material bonded at both ends. The axial ring-type composite permanent magnet is ring-shaped in the center of the rotating shaft, leaving a certain gap between it and the rotating shaft;

The rotating shaft is made of magnetic isolation material;

The circumferentially staggered rotor is a composite structure, including a tubular magnet and a rotor yoke on the periphery of the tubular magnet. Four salient poles, namely rotor teeth, are evenly distributed on the rotor yoke. The rotor yoke and rotor teeth are laminated by silicon steel sheets. The tubular magnet is closely combined with the rotor yoke to ensure the corresponding rigidity for high-speed rotation; the two sets of circumferentially staggered rotors are fixed to the rotating shafts on both sides of the axial ring-type composite permanent magnets in a circumferentially staggered manner, and are connected to the rotating shaft. coaxial rotation;

The magnetic isolation stator is made of laminated isolated silicon steel sheets, including an isolated stator yoke and 6 salient poles, namely stator teeth, evenly distributed on it; each convex stage is wound with an excitation winding with the same number of turns; two groups The magnetic isolation stator is arranged corresponding to the two sets of circumferentially staggered rotors. There is a certain air gap between the magnetic isolation stator and the circumferential staggered rotor. The casing is coaxially arranged with the rotating shaft, and six parallel strips are arranged on the inner wall of the casing. The protruding magnetic isolation strips on the rotating shaft form a magnetic isolation groove, and the magnetic isolation stator is fixed in the magnetic isolation groove of the casing; the magnetic isolation groove is used to isolate the magnetic leakage magnetic circuit between adjacent stator teeth, and The partition-type stator yoke is fixed to prevent it from falling off due to the magnetic moment generated between the stator and rotor teeth of the motor; the casing is made of magnetic isolation material.

The middle part of the casing is provided with a device for fixing the axial ring-type composite permanent magnet and the magnetic conductive strip, so that the axial ring-type composite permanent magnet and the magnetic conductive strip are fixed in the middle part of the casing. The number of the magnetic conductive strips is Six, made of magnetically permeable material, are used to connect the magnetic yokes between the stators on both sides and act as magnetic bridges.

The structures on both sides of the middle vertical surface of the rotating shaft are arranged in parallel, except for the rotor, and are completely symmetrical to the middle vertical surface of the rotating shaft.

Beneficial effects: Compared with the existing technology, the rotor staggered stator magnetic isolation type axial permanent magnet auxiliary double salient pole motor of the present invention has the following advantages:

(1) Using the permanent magnet auxiliary excitation structure, the stator excitation current is reduced through the excitation effect of the permanent magnet in the magnetic circuit, effectively reducing the copper loss of the excitation winding;

(2) The rotors on both sides are installed at a circumferential staggered angle, which increases the number of convex teeth on the motor rotor. Its special structure can be approximately regarded as a 12/8-stage structure. Compared with the classic 6/4-stage structure, the step angle is smaller. Effectively increase the output torque of the motor, improve torque smoothness and reduce noise;

(3) By adopting the bilateral excitation and rotor staggered angle synchronous control method, the torque peaks and valleys on both sides can be effectively complemented, reducing the switching frequency of electronic devices, increasing service life and effectively reducing stator and rotor core losses;

(4) The stator and rotor are made of laminated silicon steel sheets, which greatly reduces the mass of the motor, reduces the moment of inertia of the motor, reduces the complexity of motor control, and makes the stator and rotor have good magnetic permeability;

(5) The magnetic isolation stator and the magnetic bridge effectively "plan" the motor's magnetic circuit to a specific path, reducing the loss of magnetic leakage in the non-energized phase and the casing;

(6) The combination of permanent magnet auxiliary technology and stator magnetic isolation can effectively increase the increment of air gap magnetic energy and improve the motor output torque index per unit mass.

Description of the drawings

Figure 1 is a radial cross-sectional view of a rotor staggered stator magnet-isolated axial permanent magnet-assisted double salient pole motor according to an embodiment of the present invention. (a) is a two-dimensional radial cross-section, and (b) is a three-dimensional radial cross-section. sectional view;

Figure 2 is a schematic three-dimensional structural diagram of an axial ring-type composite permanent magnet according to an embodiment of the present invention;

Figure 3 is a schematic diagram of the rotor angle deviation according to an embodiment of the present invention;

Figure 4 is a side view of a rotor-staggered stator magnet-isolated axial permanent magnet-assisted double salient pole motor at different rotor positions according to an embodiment of the present invention. In (a), one side A starts to be energized, and the two sides A are already energized. The side view when power is on, (b) is the side view when phase A on both sides is de-energized, phase A on one side remains energized, and phase B on both sides starts to be energized; (c) is the side view when phase A winding on one side is de-energized, and phase B on both sides The side view when phase B on one side starts to be energized while the phases remain energized;

Figure 5 is a schematic diagram of a magnetic circuit according to an embodiment of the present invention;

Figure 6 is a schematic diagram of the motor phase inductance changing with the rotor position according to one embodiment of the present invention;

Figure 7 is a schematic diagram of a casing and a magnetic isolation stator according to an embodiment of the present invention. (a) is a schematic diagram of a casing with a magnetic isolation strip, (b) is a schematic diagram of a magnetic isolation stator, and (c) is a casing. Schematic diagram of assembly with magnetically isolated stator;

Figure 8 is a schematic diagram of a magnetic conductive strip according to an embodiment of the present invention, in which (a) is a three-dimensional schematic diagram of the motor with the casing end cover removed, and (b) is the front view of the motor with the casing end cover removed;

Figure 9 is an overall schematic diagram of a motor according to an embodiment of the present invention;

Among them, 1-shaft, 2-casing, 3-axial ring-type composite permanent magnet, 3a-permanent magnet, 3b-magnetic conductor, 4-magnetic conductive strip, 5-excitation winding, 6-end cover, 7- Tubular magnet, 8-rotor yoke, 9-salient pole, 10-isolated stator yoke, 11-stator teeth, 12-casing protrusion, 13-magnetic isolation slot, 14-magnetic strip, 15-gas gap;

FIG. 10 is a schematic diagram of the change of the magnetic common energy at a certain time according to an embodiment of the present invention.

Detailed ways

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

As shown in Figure 1-9, a rotor staggered stator magnetic isolation axial permanent magnet auxiliary double salient pole motor includes:

Two sets of magnetic isolation stators, two sets of circumferentially staggered rotors, rotating shaft 1, casing 2, axial ring-type composite permanent magnet 3, magnetic strip 4, excitation winding 5 and end cover 6.

As shown in Figure 2, the axial ring-type composite permanent magnet 3 includes a permanent magnet 3b and a magnet conductor 3a bonded at both ends. The axial ring-type composite permanent magnet 3 is ring-shaped at the center of the rotating shaft and connected with the rotating shaft. There is a certain gap between them; the magnetic conductive body 3a is made of magnetic conductive material.

The rotating shaft 1 is made of magnetic isolation material.

The use of permanent magnet auxiliary excitation can reduce the stator current without maintaining the motor output performance, saving energy. Since the permanent magnets and excitation windings simultaneously produce air gap magnetic density in the air gap, the addition of permanent magnets can correspondingly reduce the excitation current and increase the air gap magnetic density to increase the torque.

As shown in Figure 3-4, the circumferentially staggered rotor is a composite structure, including a tubular magnetizer 7 and a rotor yoke 8 around the tubular magnetizer. Four salient poles, namely rotor teeth 9, are evenly distributed on the rotor yoke. The rotor yoke 8 and the rotor teeth 9 are made of laminated silicon steel sheets. The tubular magnet 7 is closely combined with the rotor yoke 8 to ensure the corresponding rigidity for high-speed rotation. The two sets of circumferentially staggered rotors adopt the circumferential direction as shown in Figure 3. They are respectively fixed on the rotating shafts 1 on both sides of the axial ring-type composite permanent magnet 3 in a staggered angle manner, and rotate coaxially with the rotating shaft 1.

Using the circumferential staggered angle method, this motor can be approximately regarded as a 12/8-stage reluctance motor. Compared with the ordinary 6/4-stage reluctance motor, it increases the number of rotor stages, reduces the step angle, and improves the smooth output of motor torque. Stability reduces noise. The step angle is Among them, t _r is one cycle of power supply and one rotor pole pitch t _r =360/Nr, m is the number of phases, and Nr is the number of poles of the motor rotor.

As shown in Figures 4(a)-4(c), the magnetic isolation stator is made of laminated isolated silicon steel sheets, including an isolated stator yoke 10 and 6 salient poles evenly distributed along the circumference thereof, namely the stator. Teeth 11; each convex stage is wound with an excitation winding 5 with the same number of turns; two sets of magnetically isolated stators are set corresponding to two sets of circumferentially staggered rotors, and there is a certain distance between the magnetically isolated stators and the circumferentially staggered rotors. Air gap 15.

The stator and rotor adopt a salient pole design, and use the "minimum reluctance principle" to generate tangential pulling force to realize starting, braking, stopping and four-quadrant operation of the motor.

The operating principle and control method of the rotor staggered stator magnetic isolation axial permanent magnet auxiliary doubly salient motor are as follows:

The excitation windings on both sides of the axial ring-type permanent magnet are evenly divided into phase A, phase B and phase C as shown in Figure 4, and the windings on both sides are distributed symmetrically. The windings on both sides are separately controlled by two sets of control systems to achieve the magnetic flux path as shown in Figure 5. When the drive motor is running, current is passed into the stator excitation coil of one phase to generate magnetomotive force, and the stator at both ends forms N pole and S pole respectively. The magnetic flux generated by the magnetomotive force of the composite permanent magnet passes through the magnetic conductive materials at both ends. The end rotor teeth form S poles and N poles respectively, and the magnetomotive force generated by the permanent magnet 3b and the excitation winding 5 respectively acts superimposed on the closed magnetic circuit to produce an air gap magnetic density. According to the "minimum reluctance principle", tangential pulling force is generated, and the motor can be rotated by controlling the excitation winding to conduct in sequence. Motor magnetic circuit: stator convex level 11 on one side, air gap 15, rotor convex level 9 on one side, magnet conductor 7, axial ring-type composite permanent magnet 3, magnet conductor 7, rotor convex level 11 on one side, air gap 15. There are 9 convex steps on the other side of the stator, 14 magnetic conductive strips, and 11 convex steps on one side of the stator. Since the addition of permanent magnets increases the total magnetomotive force in the magnetic circuit and thereby strengthens the air gap magnetic density in the magnetic circuit, a smaller excitation current can be used to achieve a given magnetic density effect in the air gap.

Specific implementation is shown in Figure 4(a). At this time, phase A of the stator on both sides is energized. Specifically, one side A starts to be energized, and both sides A are already energized. Due to the distortion of the air gap magnetic flux, a tangential magnetic pull force is generated between the stator and the rotor. The rotor rotates clockwise; when the rotors on both sides rotate clockwise to the convex stage alignment position of the stator and rotor, as shown in Figure 4(b), at this time, phase A on both sides is powered off, phase A on one side remains energized, and phase B on both sides begins to be energized. ; The rotor continues to rotate. When the rotor on one side is aligned with the stator, as shown in Figure 4(c). At this time, the A-phase winding on one side is powered off, the B-phase on both sides remains energized, and the B-phase on one side begins to be energized, completing a phase commutation. , and so on, the motor realizes clockwise operation, and reverse rotation is opposite to the above process.

The advantage of this design using the above control strategy is that at any time during the entire control process, both sides of the windings, that is, the above-mentioned in-phase or out-of-phase windings, are energized at the same time, so that the torque on both sides can be superimposed to increase the motor output; in addition, in this implementation , there is no process under the energized phase inductance, because the size of the energized phase winding inductance changes with the change of the rotor position, as shown in Figure 6, the inductance is the largest when the stator and rotor are aligned, and the smallest in the non-aligned position. Due to the electric torque formula of switched reluctance motor:

i is the stator winding current, L is the stator winding inductance, and θ is the angle between the stator and rotor axes. During the above control process, whenever the stator and rotor on a certain side are aligned, the stator winding on that side is controlled to be powered off, thus avoiding the impact on the motor torque ripple when the inductance drops, and improving the torque ripple problem compared to ordinary reluctance motors.

As shown in Figures 7(a)-7(c), the casing 2 is coaxially arranged with the rotating shaft 1, and six protrusions 12 parallel to the rotating shaft are provided on the inner wall of the casing to form magnetic isolation slots 13. The casing adopts isolation Magnetic materials eliminate the iron loss on traditional motor casings. The protrusions 12 are magnetic isolation strips, which isolate the magnetic flux between adjacent stators and fix the stator to prevent it from falling off due to the magnetic torque generated between the stator and rotor teeth of the motor; among them, the isolation strip is shown in Figure 7(b) The magnetic stator is fixed in the magnetic isolation slot of the casing, which prevents the magnetic flux generated by the energized phase excitation winding from leaking to the non-energized phase stator, reducing losses.

The middle part of the casing 2 is provided with a device for fixing the axial ring-type composite permanent magnet 3 and the magnetic strip 14, so that the axial ring-type composite permanent magnet and the magnetic strip 14 are fixed in the middle part of the casing, as shown in Figure 8 ( As shown in a)-8(b), there are six magnetic conductive strips 14, which are made of magnetic conductive material and are used to connect the magnetic flux between the stators on both sides and act as a magnetic bridge.

As shown in Figure 9, end caps 6 are provided at both ends of the casing 2.

The structures on both sides of the middle vertical surface of the rotating shaft 1 are arranged in parallel except for the rotor, and are completely symmetrical to the middle vertical surface of the rotating shaft.

The principle of increasing the torque is as follows: the electromagnetic torque of the switched reluctance motor can be calculated from the electromechanical energy conversion perspective based on the magnetic common energy:

Among them, W is the magnetic common energy of the motor, as shown in Figure 10. Among them, the area enclosed by the curve OCB (or OA) and the i coordinate axis represents the magnetic common energy, which is a function of the current and flux linkage, and θ is the relative motion of the rotor. to the angular displacement of the stator. Therefore, the torque capacity of the motor can be reflected by the I-φ characteristic curve, as shown in Figure 10. The straight line OA in the figure indicates when the center line of the rotor teeth coincides with the center line of the stator slot (that is, the stator and rotor tooth axes are not aligned). The characteristic corresponds to the maximum reluctance position. At this time, because the air between the stator and rotor poles is large and the magnetic circuit is not saturated, it is a straight line OA; and the curve OCB represents the characteristics when the center lines of the stator and rotor magnetic poles are aligned, corresponding to The position of minimum magnetic resistance.

The average torque of each step forward of the rotor is proportional to the surrounding magnetic common energy increment ΔW of the area OABCO. Therefore, the average output torque of the multi-phase switched reluctance motor is:

Among them, Nr is the number of rotor poles of the motor, and m is the number of phases. Obviously, under the same magnetic field energy storage, increasing the number of phases and rotor poles of the motor can also effectively increase the output torque of the motor. However, for the traditional structure switched reluctance motor, after the outer diameter of the motor is determined, there is a mutual restriction relationship between the three, which is difficult to obtain from the structure. The invention adopts a special structure equivalent to a 12/8-stage structure to increase the number of rotor poles and increase the torque.

Since the leakage flux of adjacent tooth poles of ordinary switched reluctance motors will produce braking torque on the rotor, this will greatly affect the output of the motor. Therefore, the present invention uses permanent magnet assistance. Through the axial permanent magnet, the direction of the magnetic flux of the auxiliary permanent magnet is opposite to the direction of the magnetic flux leakage in the stator and rotor cores, so that the inter-pole magnetic flux leakage is significantly reduced, and the magnetic leakage is reduced to generate braking torque.

It can also be seen from equation (3) that the torque of the switched reluctance motor can be improved by increasing the magnetic common energy increment ΔW. When the stator and rotor teeth are not aligned, the relationship between the air gap flux and current is OA in Figure 10; When the stator and rotor teeth are aligned, the relationship between air gap flux and current is shown in Figure 10 OAB; the direction of the magnetic flux of the permanent magnet is the same as the direction of the magnetic flux generated by the stator winding in the air gap, and the air gap flux is enhanced, thus strengthening the The enclosing magnetic common energy increment area ΔW of the region OABCO.

Therefore, the rotor staggered stator magnetic isolation axial permanent magnet auxiliary double salient pole motor of the present invention achieves increased torque by increasing the number of rotor stages and increasing the magnetic common energy increment ΔW.

Claims (1)

1. The utility model provides a rotor stagger angle stator separates supplementary doubly salient motor of magnetism type axial permanent magnetism which characterized in that includes:

two groups of magnetism isolating stators, two groups of peripheral Xiang Cuojiao rotors, a rotating shaft, a shell, an axial ring sleeve type composite permanent magnet and an excitation winding;

the axial annular sleeve type composite permanent magnet comprises a permanent magnet and magnetic conductive materials bonded at two ends of the permanent magnet, the axial annular sleeve type composite permanent magnet is annularly sleeved in the center of the rotating shaft, and a certain gap is reserved between the axial annular sleeve type composite permanent magnet and the rotating shaft;

the circumferential staggered rotor comprises a tubular magnetizer and rotor yokes at the periphery of the tubular magnetizer, salient poles, namely rotor teeth, are uniformly distributed on the rotor yokes, and two groups of circumferential Xiang Cuojiao rotors are respectively fixed on rotating shafts at two sides of the axial annular sleeve type composite permanent magnet and coaxially rotate with the rotating shafts;

the magnetism isolating stator comprises a partition type stator magnetic yoke and salient poles, namely stator teeth, which are uniformly distributed on the partition type stator magnetic yoke; each convex stage is wound with an excitation winding with the same number of turns; the two groups of magnetism isolating stators are respectively arranged corresponding to the two groups of peripheral Xiang Cuojiao rotors, and a certain air gap is reserved between the magnetism isolating stators and the peripheral staggered rotor;

the shell and the rotating shaft are coaxially arranged, six protruding magnetism isolating strips parallel to the rotating shaft are arranged on the inner wall of the shell to form magnetism isolating grooves, and the magnetism isolating stator is fixed in the magnetism isolating grooves of the shell;

six magnetic conducting strips are arranged between the two groups of magnetism isolating stators, and the magnetic conducting strips are made of magnetic conducting materials and are used for being connected with the magnetic yokes of the stators at two sides to serve as magnetic bridges; the axial annular sleeve type composite permanent magnet and the magnetic conducting strip are fixed in the middle of the shell;

4 salient poles are uniformly distributed on the rotor magnetic yoke, and 6 salient poles are uniformly distributed on the partition type stator magnetic yoke;

the rotating shaft is made of a magnetism isolating material;

the rotor magnetic yoke and the rotor teeth are formed by laminating silicon steel sheets, and the magnetism isolating stator is formed by laminating partition silicon steel sheets;

the two groups of peripheral Xiang Cuojiao rotors are respectively fixed on rotating shafts on two sides of the axial ring sleeve type composite permanent magnet in a circumferential staggered angle mode;

the shell is made of a magnetism isolating material, and the magnetism isolating grooves are used for isolating magnetism leakage magnetic circuits between adjacent stator teeth and fixing the isolated stator yoke to prevent the isolated stator yoke from falling off due to magnetic moment generated between stator teeth and rotor teeth of the motor.