CN105811696B - Hybrid excitation type composite flux switching permanent magnet motor - Google Patents

Abstract

A mixed excitation type composite magnetic flux switching permanent magnet motor comprises an inner rotor, an inner stator, a magnetism isolating groove, a magnetism guiding bridge, an outer stator and an outer rotor, wherein the stator part adopts a concentrated armature winding, a permanent magnet is nested on stator teeth, the rotor part is a salient pole and has no permanent magnet or winding, the concentrated excitation winding between the inner stator and the outer stator is placed in the magnetism isolating groove, the magnetism isolating groove is connected through the magnetism guiding bridge, and the structure is very firm and symmetrical. The advantages of compactness, simplicity, good robustness and suitability for high-speed operation of the permanent magnet flux switching motor are kept in the structure; the advantages of large torque output, high power density and high efficiency of the permanent magnet motor are kept in performance; the added set of electric excitation winding can isolate magnetism and adjust magnetism; the armature and the excitation windings in the motor both adopt concentrated windings, and the end parts are shorter; compared with the existing hybrid excitation motor, the hybrid excitation motor has a simple structure, and the excitation winding does not occupy the slot area of the armature winding but can bidirectionally adjust the magnetic field of the motor.

Description

Hybrid Excitation Composite Flux Switching Permanent Magnet Motor

technical field

The invention relates to the technical field of motor manufacturing, in particular to a motor capable of realizing a hybrid excitation function.

Background technique

With the intensification of the energy crisis, it has become the consensus of the world to use permanent magnet excitation instead of electric excitation to save energy consumption. At the same time, since my country is the country with the richest rare earth resources in the world, it is necessary to develop, research and promote the application of new structure rare earth permanent magnets. Motor has important theoretical significance and practical value. Especially for hybrid electric vehicles, which are widely studied at present, the motor drive system is required to be small in size, light in weight, high in efficiency, strong in reliability, free of maintenance, large in torque output, and wide in speed regulation range. However, the permanent magnet motor itself has the bottleneck that the air gap magnetic field cannot be adjusted, which limits its application in hybrid electric vehicles.

The vast majority of permanent magnet motor no-load permanent magnet flux linkage is greater than the product of direct axis inductance and rated current, the maximum torque of permanent magnet motor in the constant torque region and the maximum operating speed in the constant power region are a pair that cannot Reconcile the contradiction: on the one hand, increasing the permanent magnet flux linkage can certainly improve the maximum torque output capability of the motor, but at the same time limit the high-speed operation of the motor (due to the increasing no-load back electromotive force); on the other hand, when the inverter When the current limit of the motor and the direct axis inductance of the motor are fixed, reducing the permanent magnet flux linkage is beneficial to improve the constant power operating range of the motor but will limit the torque output. Therefore, the above-mentioned shortcoming of the permanent magnet motor has become a bottleneck restricting its application and popularization. Most of the current hybrid excitation motors based on rotor permanent magnet motors place the DC excitation winding on the stator. In order to provide a path parallel to the permanent magnet flux in the radial or axial direction for the electric excitation flux, the proposed motor structure is very complicated, and it faces huge challenges in terms of manufacturing process and mass production of finished products. challenge. If a hybrid excitation motor needs to make a significant sacrifice in terms of structural complexity in order to achieve magnetic field adjustment, its competitiveness will be greatly reduced.

On the other hand, since the end of the last century, three new stator permanent magnet motors have emerged in the world, namely double salient permanent magnet motors, flux switching permanent magnet motors and flux inversion permanent magnet motors. In order to place both permanent magnets and armature windings in the stator, the rotor is only made of soft magnetic materials such as silicon steel sheets. The mixed excitation structure schemes for the former two have been proposed. The present invention proposes a new type of hybrid excitation flux inversion motor based on the structure of the flux inversion permanent magnet motor to avoid complex structures. And try to realize the mixed excitation function without making major modifications on the basis of maintaining the pure permanent magnet motor.

Contents of the invention

The purpose of the invention is to propose a hybrid excitation type flux reversing motor with a novel structure on the basis of the structure of the flux reversing permanent magnet motor, so as to avoid complex structures and try to keep the pure permanent magnet motor on the basis of The hybrid excitation function can be realized without major modification.

The technical solution adopted by the present invention to achieve the above object is: a hybrid excitation type composite flux switching permanent magnet motor, including an inner rotor 3-1, an inner stator 3-3, a magnetic isolation slot 2-2, and a magnetic bridge 2-1 , the outer stator 1-3 and the outer rotor 1-1, the outer stator 1-3 is located inside the outer rotor 1-1 to form an outer rotor structure, the outer rotor 1-1 and the outer stator 1-3 are salient pole structures, each An outer stator tooth is nested with an outer motor permanent magnet 1-2, and the outer stator tooth is provided with an outer motor three-phase concentrated armature winding 1-4; the inner rotor 3-1 is located inside the inner stator 3-3, forming an inner rotor structure, the inner rotor 3-1 and the inner stator 3-3 are salient pole structures, each inner stator tooth is nested with an inner motor permanent magnet 3-2, and the inner stator teeth are provided with an inner motor three-phase concentrated armature winding 3 -4; The magnetic bridge (2-1) and the magnetic isolation slot 2-2 are distributed between the outer stator 1-3 and the inner stator 3-3, and the magnetic isolation slot 2-2 is provided with an excitation coil 2-3; each The set of stators contains two inner and outer stators. The polarities of the two permanent magnets under each set of stator teeth are opposite, and the polarity distribution of the magnetic steel under the adjacent stator teeth is staggered; each excitation coil 2-3 in the magnetic isolation slot 2-2 is connected to Adjacent excitation coils 2-3 are connected in series in antiphase to form a single-phase excitation winding.

The magnetic bridge 2-1 is made of laminated silicon steel sheets, and its thickness is 1/3 of the thickness of the stator yoke.

The three-phase concentrated armature windings 1-4 of the outer motor, the three-phase concentrated armature windings 3-4 of the inner motor and the field coil 2-3 are all concentrated windings.

The inner rotor 3-1 and the outer rotor 1-1 are straight-slot or skewed-slot rotors.

Both the outer stator 1-3 and the inner stator 3-3 are assembled with a magnetically conductive core and a permanent magnet, and the iron core part is composed of a magnetically conductive core.

In the hybrid excitation type composite flux switching permanent magnet motor of the present invention, on the one hand, the stator part adopts concentrated armature windings, the permanent magnets are nested on the stator teeth, and the rotor part is a salient pole without permanent magnets or windings. On the one hand, the concentrated excitation windings between the inner and outer stators are placed in the magnetic isolation slots, and the magnetic isolation slots are connected by magnetic bridges. Excitation current is controlled. In terms of structure, the permanent magnet flux switching motor has the advantages of being compact, simple, robust, and suitable for high-speed operation; in terms of performance, it retains the advantages of permanent magnet motor with large torque output, high power density, and high efficiency; An additional set of electric excitation windings can isolate and adjust the magnetic field; both the armature and the excitation windings in the motor are concentrated windings, and the ends are shorter; it is compatible with the existing hybrid excitation motors (including rotor permanent magnet type and Stator permanent magnet type) is simpler in structure than the field winding, which will not occupy the slot area of the armature winding, but will adjust the motor magnetic field bidirectionally; it is especially suitable for applications requiring small volume and large output, and can realize large rotation in the constant torque area Wide speed regulation function in torque and constant power area.

Description of drawings

Fig. 1 is a structure diagram of a hybrid excitation compound flux switching permanent magnet motor of the present invention.

Fig. 2 is a schematic diagram of a hybrid excitation compound flux switching permanent magnet motor of the present invention.

In the figure: outer rotor 1-1, outer motor permanent magnet 1-2, outer stator 1-3, outer motor three-phase concentrated armature winding 1-4, magnetic bridge 2-1, magnetic isolation slot 2-2, excitation Coil 2-3, inner rotor 3-1, inner motor permanent magnet 3-2, inner stator 3-3, inner motor three-phase concentrated armature winding 3-4, outer structure permanent magnet flux path 4-1, outer structure Excitation flux path 4-2, internal structure permanent magnet flux path 5-1, internal structure excitation flux path 5-2.

Detailed ways

The hybrid excitation type composite flux switching permanent magnet motor of the present invention has a structure as shown in Figure 1, comprising: a stator, a permanent magnet, a three-phase concentrated armature winding, a single-phase concentrated excitation winding, a magnetic isolation slot 2-2, and a magnetic bridge 2-1 and the rotor, its structure can be equivalent to a composite of two permanent magnet flux switching motors connected by a magnetic bridge and a magnetic isolation slot, and the structures from inside to outside are: inner rotor 3-1, inner stator 3-3, magnetic isolation slot 2-2, magnetic bridge 2-1, outer stator 1-3 and outer rotor 1-1, outer stator 1-3 is located inside outer rotor 1-1, forming an outer rotor structure, outer Both the rotor 1-1 and the outer stator 1-3 have a salient pole structure, wherein the outer stator core part is composed of a magnetic core, and each stator tooth is nested with an outer motor permanent magnet 1-2, and an outer stator tooth is provided with an outer The three-phase concentrated armature winding 1-4 of the motor; the magnetic bridge 2-1 and the magnetic isolation slot 2-2 are distributed between the outer stator 1-3 and the inner stator 3-3 at intervals, and the excitation coil is placed in the magnetic isolation slot 2-2 2-3; the inner rotor 3-1 is located inside the inner stator 3-3 to form an inner rotor structure, both the inner rotor 3-1 and the inner stator 3-3 are salient pole structures, and the inner stator core part is composed of a magnetic core , each stator tooth is nested with an inner motor permanent magnet 3-2, and an inner motor three-phase concentrated armature winding 3-4 is arranged on the inner stator tooth. The magnetic isolation slot 2-2 and the magnetic bridge 2-1 are spaced and distributed between the inner stator 3-3 and the outer stator 1-3. Each set of stators contains two inner and outer stators, such as stator tooth A1 and stator tooth a1. There are permanent magnets embedded in each stator core, the polarity of the two permanent magnets under each set of stator teeth is opposite, and the polarity distribution of the magnetic steel under the adjacent stator teeth is staggered, that is, the polarity distribution of the permanent magnets under the first set of stator teeth If it is NS, then the polarity of the permanent magnet under the adjacent set of stator teeth is SN. The excitation coil is placed in the magnetic groove to achieve the functions of magnetic isolation and magnetic adjustment. If the number of inner and outer stator teeth is P _s , there are a total of 2 P _s permanent magnets nested in the stator teeth, and a total of P _s magnetic isolation slots are provided for the field winding. The coils of each set of three-phase concentrated armature windings span across each set of stator teeth. Taking the outer stator as an example, the three-phase concentrated armature windings have a total of P _s concentrated armature coils in the order of ABC three-phase Alternately distributed, each phase is composed of P _s /3 armature coils, and the coils belonging to the same phase are spatially different from each other by 1080 ^o / P _s (spatial mechanical angle). If a hybrid excitation composite flux switching permanent magnet motor with 12 slots in the stator and 10 poles in the rotor is taken as an example, the first concentrated armature coil, the fourth concentrated armature coil, the seventh concentrated armature coil and the tenth concentrated armature coil Concentrated armature coils (with a space difference of 90 ^o ) are sequentially connected in series (or in parallel) to form A-phase armature windings; then the second concentrated armature coil, the fifth concentrated armature coil, the eighth concentrated armature coil and the Eleven concentrated armature coils (space difference ^90o ), sequentially connected in series (or parallel) to form B-phase armature winding; then the third concentrated armature coil, the sixth concentrated armature coil, the ninth concentrated armature coil and the twelfth concentrated armature coil (with a space difference of 90 ^o ), which are sequentially connected in series (or in parallel) to form the C-phase armature winding; for the 4 armature winding coils forming the A-phase, the four concentrated coils are in For any rotor position, the number of flux linkages in the windings is the same and the direction is the same, and they are directly connected in series to form phase A, and the situation for phase B and phase C is similar. The armature winding is a concentrated winding, and the excitation winding is also a concentrated winding. Each concentrated excitation coil in the magnetic isolation slot is connected in reverse phase with an adjacent excitation coil to form a single-phase excitation winding. The inner and outer stators are assembled with permeable core and permanent magnet. The magnetic bridge is made of laminated silicon steel sheets, and its thickness is generally designed to be 1/3 of the thickness of the stator yoke. The rotor is a straight slot or inclined slot rotor with neither permanent magnets nor windings on the rotor. Permanent magnets are ferrite, samarium cobalt or neodymium iron boron and other types of permanent magnet materials.

When the excitation winding does not pass current, because the magnetic bridge 2-1 is extremely thin and the permanent magnetic potential is relatively large, the magnetic bridge 2-1 is very easy to lead to saturation. At this time, the structure can be regarded as two independent permanent magnets. Flux switching motors. In the present invention, a magnetic isolation slot 2-2 and a magnetic bridge 2-1 are added between the inner and outer stators, and an excitation coil 2-3 is placed in the magnetic isolation slot 2-2, so that the effect of magnetic field weakening and speed expansion can be achieved. Feed the corresponding DC excitation current to the excitation coil 2-3 to make it generate an electric excitation magnetic potential opposite to the direction of the permanent magnetic potential in the magnetic bridge 2-1. At this time, the permanent magnetic potential ensures the saturation of the magnetic bridge. , it is also necessary to cancel the electric excitation magnetic potential in the opposite direction, so the permanent magnet flux linkage in the stator will be weakened. By adjusting the area of the magnetic isolation slot 2-2 and the size of the excitation current density, the size of the electric excitation magnetic potential can be adjusted, so that the purpose of magnetic adjustment and speed expansion can be achieved according to the designer's requirements, and the shortcomings of the pure permanent magnet motor can be overcome.

As shown in Figure 1, take a motor with 12 slots/10 poles both inside and outside the stator/rotor as an example. The outer stator 1-3 has 12 teeth, and each stator tooth is nested with the permanent magnet 1-2 of the outer motor, and the outer stator teeth There are three-phase concentrated armature windings 1-4 of the outer motor; the inner stator 3-3 has 12 teeth, each stator tooth is nested with the permanent magnet 3-2 of the inner motor, and an inner motor is arranged on the inner stator teeth Three-phase concentrated armature winding 3-4; the four winding coils of phase A of the outer motor armature winding 1-4 are respectively placed in the slots on both sides of each tooth in the outer stator 1-3, and the four concentrated winding coils are in the same direction Phase A is formed in series; the four winding coils of phase B of the armature windings 1-4 of the outer motor are respectively placed in the slots on both sides of each tooth in the outer stator 1-3, and the four concentrated winding coils are connected in series in the same direction to form A phase; the four winding coils of the C phase of the armature winding 1-4 of the outer motor are respectively placed in the slots on both sides of each tooth in the outer stator 1-3, and the four concentrated winding coils are connected in series in the same direction to form the A phase; The four winding coils of the A phase of the motor armature winding 3-4 are respectively placed in the slots on both sides of each tooth in the outer stator 3-3, and the four concentrated winding coils are connected in series in the same direction to form the A phase; the inner motor armature winding The four winding coils of the B phase of 3-4 are respectively placed in the slots on both sides of each tooth in the outer stator 3-3, and the four concentrated winding coils are connected in series in the same direction to form the B phase; the inner motor armature winding 3-4 The four winding coils of the C phase are respectively placed in the slots on both sides of each tooth in the outer stator 3-3, and the four concentrated winding coils are connected in series in the same direction to form the C phase; the excitation winding 2-3 has a total of 12 concentrated coils , placed in the magnetic isolation slot between the inner and outer stator teeth. The polarities of the two coils in each magnetic separation slot are the same, and the 12 adjacent excitation windings are connected in series in reverse phase at one time to form a single-phase double-layer excitation winding. Both the inner and outer stators 1-3 and 3-3 contain 12 stator teeth, each stator is embedded with permanent magnets, and the polarities of the permanent magnets under each set of stator teeth are opposite, that is, the inner stator and the outer stator on the same radial direction are embedded The sets of permanent magnets are of opposite polarity. Also, tangentially adjacent permanent magnets are opposite in polarity.

As shown in Figure 2, when the motor rotor is in this position, both the inner and outer rotors have a tooth that is aligned with the stator teeth. According to the magnetization direction of the permanent magnet, the permanent magnet flux direction in the two armature coils has the largest value. Therefore, if the electric excitation magnetic potential opposite to the direction of the permanent magnetic field is applied through the magnetic winding coil, so that the direction of the generated electric excitation magnetic flux is opposite to that of the permanent magnetic flux, the synthetic flux linkage in the inner and outer armature coils can be reduced at the same time , thereby reducing the potential induced in the armature winding. As shown in the permanent magnet flux linkage 4-1 in Figure 2, when the motor rotor is in the position shown in Figure 2, take the outer motor as an example, the outer stator 1-3 has a tooth that is opposite to the rotor tooth of the outer rotor 1-1, according to The magnetization direction of the permanent magnet is judged. The permanent magnetic flux of the turn chain in the coil passes through the stator tooth and penetrates into the rotor pole through the air gap. At this time, the permanent magnetic flux value is the largest. Passing a weak magnetic current to the excitation winding will generate an electric excitation flux linkage opposite to the permanent magnet magnetic potential, as shown in the excitation flux linkage 4-2 in Figure 2, the excitation flux linkage passes through the rotor teeth, passes through the air gap, and penetrates into the stator. The sub, which reduces the magnetic flux linked by the armature coil, thereby reducing the induced potential. Again, the internals have the same working principle. At the same time, electric excitation and permanent magnet are used as the excitation source of the motor, which can greatly improve the controllability of the air gap magnetic field of the motor, thereby improving the performance and working efficiency of the motor.

The permanent magnets 1-2 and 3-2 of the inner and outer structures are ferrite, samarium cobalt or neodymium iron boron and other types of permanent magnet materials, the inner and outer stators 1-3, 3-3, the inner and outer rotors 1-1, 3-1 and The magnetic bridge can be made of silicon steel sheet punched and laminated, and the magnetic isolation slot 2-2 opened between the inner and outer stators is used to place the excitation winding.

In addition, the characteristics of the structure of the motor lead to a large no-load air gap flux density, and the motor has a strong torque output capability and a high power density; at the same time, the armature winding and the field winding are concentrated windings, and the end Short, small resistance, high efficiency.

The present invention has been described by means of embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, the features and examples may be modified to adapt a particular situation and material to the teachings of the invention without departing from the spirit and scope of the invention. Therefore, the present invention is not limited by the specific embodiments disclosed here, and all embodiments falling within the scope of the claims of the present application belong to the protection scope of the present invention.

Claims (5)

1. Hybrid excitation compound flux switching permanent magnet motor, characterized in that it includes inner rotor (3-1), inner stator (3-3), magnetic separation slot (2-2), magnetic bridge (2-1 ), the outer stator (1-3) and the outer rotor (1-1), the outer stator (1-3) is located inside the outer rotor (1-1), forming the outer rotor structure, the outer rotor (1-1) and the outer The stators (1-3) are salient pole structures, and each outer stator tooth is nested with an outer motor permanent magnet (1-2), and the outer stator teeth are provided with an outer motor three-phase concentrated armature winding (1-4), The three-phase concentrated armature winding (1-4) of the outer motor spans the teeth of the outer stator; the inner rotor (3-1) is located inside the inner stator (3-3), forming an inner rotor structure, and the inner rotor (3-1 ) and the inner stator (3-3) are salient pole structures, each inner stator tooth is nested with inner motor permanent magnets (3-2), and the inner stator teeth are provided with inner motor three-phase concentrated armature windings (3- 4), the three-phase concentrated armature winding (3-4) of the inner motor spans the teeth of the inner stator; the magnetic bridge (2-1) and the magnetic isolation slot (2-2) are distributed on the outer stator (1-3) at intervals Between the stator and the inner stator (3-3), there is an excitation coil (2-3) in the magnetic isolation slot (2-2); each set of stators contains two inner and outer stators, and two permanent magnet poles under each set of stator teeth opposite, the polarity distribution of the magnetic steel under the adjacent stator teeth is staggered; each excitation coil (2-3) in the magnetic isolation slot (2-2) is connected in reverse phase with the adjacent excitation coil (2-3) to form a single phase field winding. 2. The hybrid excitation composite flux switching permanent magnet motor according to claim 1, characterized in that: the magnetic bridge (2-1) is made of laminated silicon steel sheets, and its thickness is 1/2 of the thickness of the stator yoke. 1/3. 3. The hybrid excitation compound flux switching permanent magnet motor according to claim 1, characterized in that: the three-phase concentrated armature windings (1-4) of the outer motor, the three-phase concentrated armature windings (3-4) of the inner motor -4) and excitation coil (2-3) are concentrated windings. 4. The hybrid excitation compound flux switching permanent magnet motor according to claim 1, characterized in that: the inner rotor (3-1) and the outer rotor (1-1) are straight-slot or inclined-slot rotors. 5. The hybrid excitation type compound flux switching permanent magnet motor according to claim 1, characterized in that: the outer stator (1-3) and the inner stator (3-3) are assembled with a magnetic core and a permanent magnet Formed, the core part is composed of a magnetic core.