Rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor
Technical Field
The invention belongs to the technology of hybrid permanent magnet motors, and particularly relates to a rotor permanent magnet type dual-rotor axial magnetic field hybrid excitation flux switching motor.
Background
The permanent magnet flux switching motor generally adopts a double salient pole structure, an armature winding and a permanent magnet are both positioned on a stator, and a rotor has no winding or permanent magnet, so that the permanent magnet flux switching motor has the advantages of high power density, high torque density, high efficiency and the like. Because the inherent characteristics of the permanent magnet lead the air gap field of the motor to be constant and difficult to adjust, the speed regulation range of the motor is narrow, and the application of the permanent magnet in the fields of constant voltage power generation and wide range speed regulation driving is limited, thereby realizing the effective adjustment of the air gap field in the permanent magnet flux switching motor and becoming a research hotspot of scholars at home and abroad.
In 2001, the german scholars Vlado Ostovic proposed the concept of a memory motor, which is also called a variable magnetic flux motor, wherein the magnetization state of a permanent magnet can be adjusted on line through direct current magnetization current or direct axis armature current according to load and rotating speed, so that an air gap magnetic field is adjusted, and the motor can run efficiently. The magnetization state of the permanent magnet can be changed by applying short pulse current due to the characteristics of the adopted permanent magnet material, so that the adjustment of an air gap magnetic field is facilitated.
In the stator permanent magnet type axial magnetic field flux switching motor, the permanent magnet is positioned in the stator, so that the area of an armature winding slot is seriously extruded, a magnetic circuit of a stator tooth part is seriously saturated, the copper loss of a motor winding and the iron loss of the stator are sharply increased, the torque capacity of the motor in an overload state is weakened, the motor is seriously heated integrally, and the service life and the reliability of the motor are adversely affected.
Disclosure of Invention
The invention aims to provide a rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor, which solves the problems of high electric excitation loss, poor overload capacity, low heat dissipation efficiency and the like of a stator permanent magnet type hybrid excitation motor in the prior art.
The technical scheme for realizing the purpose of the invention is as follows: a rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor comprises a first stator, a second stator and a rotor, wherein the first stator and the second stator are coaxially installed, the rotor is positioned between the two stators, an air gap is reserved between the two stators, and a permanent magnet is arranged on the rotor; the first stator, the second stator and the rotor are of salient pole topological structures, and the first stator and the second stator are symmetrically arranged relative to the rotor;
the first stator and the second stator comprise stator magnetic conductive iron cores and armature windings; the rotor includes rotor teeth and a field regulating winding.
Further: the magnetic conduction iron cores (5) in the first stator (1) and the second stator (3) are uniformly arranged to form a circular ring shape; the upper rotor teeth (6) on the rotor (2) are uniformly arranged to form a circular ring shape, and gaps exist between the adjacent rotor teeth (6).
Further: the number of the magnetic conduction iron cores (5) on the first stator (1) and the second stator (3) is 6n, the number of the rotor teeth (6) on the rotor (2) is 12 +/-k, and k and n are positive integers.
Further: the rotor teeth (6) comprise a first rotor pole (6-1) and a second rotor pole (6-2); each rotor tooth (6) is provided with a permanent magnet and the permanent magnet is arranged between the first rotor pole (6-1) and the second rotor pole (6-2).
Further: the permanent magnets comprise a high-coercivity permanent magnet (9) and a low-coercivity permanent magnet (8); the high-coercivity permanent magnet (9) is close to the second rotor pole (6-2), the low-coercivity permanent magnet (8) is close to the first rotor pole (6-1), the high-coercivity permanent magnet (9) and the low-coercivity permanent magnet (8) are magnetized in the tangential direction, the magnetizing directions of the high-coercivity permanent magnets (9) on adjacent rotor teeth (6) are opposite, and the initial magnetizing direction of the low-coercivity permanent magnet (8) is the same as the magnetizing direction of the high-coercivity permanent magnets (9) on the same rotor tooth (6).
Further: the stator magnetic core (5) comprises a first stator tooth (5-1), a third stator tooth (5-3), a second stator tooth (5-2) positioned between the first stator tooth (5-1) and the third stator tooth (5-3) and a stator yoke part (5-4) used for connecting the three stator teeth together, and parallel stator slots (5-5) are arranged between the second stator tooth (5-2) and the first stator tooth (5-1) and the third stator tooth (5-3) on two sides.
Further: the stator magnetic conductive iron core (5) is formed by laminating and pressing silicon steel sheets.
Further: first rotor utmost point (6-1) and second rotor utmost point (6-2) are folded by the silicon steel sheet and are pressed and make, high coercivity permanent magnet (9) adopt the neodymium iron boron permanent magnet, low coercivity permanent magnet (8) adopt alnico permanent magnet or samarium cobalt permanent magnet.
Further: the armature winding (4) is wound at the root of the second stator tooth (5-2) of each stator magnetic conductive iron core (5) respectively.
Further: the magnetic regulating windings (7) are wound on first rotor poles (6-1) of the rotor teeth (6), two magnetic regulating windings (7) are wound on each first rotor pole (6-1), and the two magnetic regulating windings (7) are respectively positioned on two sides of the low-coercivity permanent magnet (8).
Compared with the prior art, the rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor has the following advantages:
1. the permanent magnet is arranged on the rotor, so that the torque density and the power density are improved, the torque capacity of the motor in an overload state is enhanced, and the cogging torque of the motor is reduced;
2. the motor is provided with a magnetic regulating winding independently, the magnetization state of the low coercive force permanent magnet is changed by applying direct current magnetization pulse, and the air gap magnetic field is regulated.
3. The high-coercivity and low-coercivity permanent magnet is adopted for mixed excitation, the air gap magnetic field is continuously adjustable while the motor can keep high power density, and the motor has a large operation range and high efficiency.
4. The magnetization state of the low-coercivity permanent magnet is changed by applying the magnetization pulse, and the permanent magnet maintains the magnetization state after the pulse is ended, so that pricking current does not need to be continuously applied, and the magnetic regulation loss is greatly reduced.
The invention is further described below with reference to the accompanying drawings.
Drawings
Fig. 1 is a schematic structural diagram of a rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor.
Fig. 2 is a schematic structural diagram of a rotor of the rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor.
Fig. 3 is a schematic structural diagram of a stator core of a rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor according to the invention.
FIG. 4 shows that the rotor angle of the rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor of the invention is alpha1Time permanent magnetic flux path diagram.
FIG. 5 shows that the rotor angle of the rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor of the invention is alpha2Time permanent magnetic flux path diagram.
Fig. 6 is a magnetic flux operation schematic diagram of the rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet magnetic flux switching motor in the forward magnetization process.
Fig. 7 is a flux operation schematic diagram of the rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor of the invention when magnetized in the reverse direction.
In the figure, 1, a first stator, 2, a rotor, 3, a second stator, 4, an armature winding, 5, a stator magnetic core, 5-1, a first stator tooth, 5-2, a second stator tooth, 5-3, a third stator tooth, 5-4, a stator slot, 5-5, a stator yoke, 6, a rotor tooth, 6-1, a first rotor pole, 6-2, a second rotor pole, 7, a magnetic regulating winding, 8, a low coercive force permanent magnet, 9, a high coercive force permanent magnet, 10, a low coercive force permanent magnet initial magnetizing direction, 11, a high coercive force permanent magnet initial magnetizing direction and 12, the rotor angle is alpha1Permanent magnet flux path, 13. rotor angle alpha2A time permanent magnetic flux path, 14, a direct current magnetization flux path in forward magnetization, 15, a permanent magnetic flux path in forward magnetization, 16, a direct current magnetization flux path in reverse magnetization, and 17, a permanent magnetic flux path in reverse magnetization.
Detailed Description
With reference to fig. 1, a rotor permanent magnet type double-stator axial magnetic field hybrid permanent magnet flux switching motor includes a first stator 1, a second stator 3, and a rotor 2, which is coaxially installed and located between the two stators and has an air gap between the two stators; the permanent magnet is arranged on the rotor, the first stator 1, the second stator 3 and the rotor 2 are all in a salient pole topological structure, and the first stator 1 and the second stator 3 are symmetrically arranged relative to the rotor 2; the first stator 1 and the second stator 3 both comprise a stator magnetic conducting iron core 5 and an armature winding 4; the rotor 2 comprises rotor teeth 6 and a field regulating winding 7.
The number of the magnetic conduction iron cores 5 on the first stator 1 and the second stator 3 is 6n, the magnetic conduction iron cores 5 in the first stator 1 and the second stator 3 are uniformly arranged into a ring shape, the number of the rotor teeth 6 on the rotor 2 is (12 +/-k) n, the rotor teeth 6 on the rotor 2 are uniformly arranged into a ring shape, and a gap exists between every two adjacent rotor teeth 6; wherein k and n are positive integers.
Referring to fig. 2, the rotor teeth 6 are composed of a first rotor pole 6-1 and a second rotor pole 6-2, the rotor teeth 6 have a symmetrical structure, and the cross-sectional areas of the first rotor pole 6-1 and the second rotor pole 6-2 are the same. The permanent magnets comprise high-coercivity permanent magnets 9 and low-coercivity permanent magnets 8, the high-coercivity permanent magnets 9 and the low-coercivity permanent magnets 8 are arranged between a first rotor pole 6-1 and a second rotor pole 6-2, the high-coercivity permanent magnets 9 are close to the second rotor pole 6-2 and fixed on the second rotor pole 6-2, the low-coercivity permanent magnets 8 are close to the first rotor pole 6-1 and fixed on the first rotor pole 6-1, the high-coercivity permanent magnets 9 and the low-coercivity permanent magnets 8 are magnetized in the tangential direction, the magnetizing directions of the adjacent high-coercivity permanent magnets 9 are opposite, and the initial magnetizing direction of the low-coercivity permanent magnets 8 is the same as the magnetizing direction of the high-coercivity permanent magnets 9 on the same rotor tooth.
Referring to fig. 3, the stator magnetic core 5 includes a first stator tooth 5-1, a third stator tooth 5-3, a second stator tooth 5-2 located between the first stator tooth 5-1 and the third stator tooth 5-3, and a stator yoke 5-4 for connecting the three stator teeth together, the stator yoke 5-4 is fixedly connected with the first stator tooth 5-1, the second stator tooth 5-2, the third stator tooth 5-3, and a stator slot 5-5 is provided between the second stator tooth 5-2 and the first stator tooth 5-1 and the third stator tooth 5-3 on both sides.
The armature winding 4 is respectively wound at the root of the second stator tooth 5-2 of each stator magnetic conductive iron core 5, that is, the second stator tooth 5-2 is close to the stator yoke part 5-4. The magnetic regulating windings 7 are wound on first rotor poles 6-1 of the rotor teeth 6, two magnetic regulating windings 7 are wound on each first rotor pole 6-1, and the two magnetic regulating windings 7 are respectively positioned on two sides of the low-coercivity permanent magnet 8.
The stator magnetic conductive iron core 5, the first rotor pole 6-1 and the second rotor pole 6-2 are formed by silicon steel sheets in an overlying mode, the high-coercivity permanent magnet 9 is an NdFeB permanent magnet, and the low-coercivity permanent magnet 8 is an AlNiCo permanent magnet or a samarium cobalt permanent magnet.
The working operation principle of the motor is as follows: firstly, introducing a magnetic flux switching principle, wherein the initial magnetizing direction of the low-coercivity permanent magnet and the initial magnetizing direction of the high-coercivity permanent magnet are marked in fig. 4 to 7; rotor angle of alpha1The permanent magnetic flux path 12 is shown in fig. 4, and is described by taking phase a as an example, where the winding a1 is the armature winding 4 on the first stator 1, and the winding a2 is the armature winding 4 on the second stator 3; according to the principle of minimum magnetic resistance, permanent magnetic flux penetrates into windings A1 and A2 in the direction of an arrow; rotor angle of alpha1The permanent magnetic flux path 13 is shown in fig. 5, with the flux exiting the a1, a2 windings in the direction of the arrows. The permanent magnetic fluxes of the A1 and A2 winding coils at the two positions have the same value and opposite polarity, and when the rotor teeth 6 continuously rotate, the permanent magnetic fluxes of the A1 and A2 winding coils periodically change between positive and negative amplitudes, and correspondingly generate induced electromotive force with the amplitudes and phases alternately changing.
And then, introducing a mixed permanent magnet principle of the motor, wherein the mixed permanent magnet motor is related to the characteristics of the adopted permanent magnet material, the low-coercivity permanent magnet 8 can be positively magnetized and negatively magnetized by applying pulse current to the magnetic regulating winding 7, and the permanent magnet can always keep the magnetized state after the demagnetization pulse is removed. When the motor normally operates, the magnetizing direction of the low-coercivity permanent magnet 8 is consistent with the magnetizing direction of the high-coercivity permanent magnet 9 on the same rotor tooth 6, in fig. 6, a dotted line shows a direct-current magnetization magnetic flux path 14 during forward magnetization, a solid line shows a permanent-magnet magnetic flux path 15 during forward magnetization, and when a forward pulse magnetization current is applied to completely magnetize the low-coercivity permanent magnet 8, a maximum air gap magnetic field can be obtained; when the motor is in light load or high-speed rotation, the air gap magnetic field needs to be reduced, the low-coercivity permanent magnet 8 can be reversely magnetized, in fig. 7, a dotted line represents a direct-current magnetized magnetic flux path 16 during reverse magnetization, a solid line represents a permanent-magnet magnetic flux path 17 during reverse magnetization, and pulse current in the direction shown in the figure is applied to reversely magnetize the low-coercivity permanent magnet 8 to generate reverse magnetic flux to counteract the magnetic flux generated by the high-coercivity permanent magnet 9. Based on the permanent magnetic properties of the low coercive force permanent magnet 8, the permanent magnet can maintain its magnetized state after the dc magnetization pulse is removed, so as to maintain the permanent magnetic flux required by the above-mentioned motor. Therefore, the motor can continuously adjust the magnetization state of the permanent magnet through direct current magnetization current pulses according to the load and the rotating speed, and change the air gap magnetic field; the hybrid permanent magnet motor can keep high output power in a large speed range and has high efficiency.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.