CN101651394B - Mixed excitation magnetoelectric machine adopting harmonic excitation - Google Patents

Abstract

A hybrid excitation permanent magnet motor adopting harmonic excitation, comprising a casing 1, a stator core 2, a stator winding 3, a permanent magnet pole 4, a ferromagnetic pole 5, a rotating shaft 6, a rotor core 7, and a rotor winding 8, and the rotor pole consists of The permanent magnet pole 4 and the ferromagnetic pole 5 are composed of the rotor winding 8 arranged on the ferromagnetic pole 5, the rotor winding 8 is composed of the harmonic winding 14 and the excitation winding 13; the stator winding 3 is composed of the main winding 11 and the harmonic excitation winding 12, Distributed in the stator slot; the pole pitch of the main winding is the same as that of the rotor excitation winding; the pole pitch of the harmonic excitation winding is the same as that of the rotor harmonic winding; the harmonic excitation winding is connected to the excitation controller, and the motor can be controlled Harmonic excitation of the current in the winding to achieve the effect of adjusting the magnetic field and voltage; compared with the prior art, the present invention has no brush and collector ring, simple structure, no additional air gap, no axial magnetic circuit, and magnetic flux leakage Small, small electric excitation loss, high motor efficiency, and strong ability to adjust the main magnetic field.

Description

Hybrid Excitation Permanent Magnet Motor Using Harmonic Excitation

technical field

The invention relates to a permanent magnet motor, in particular to a hybrid excitation permanent magnet motor adopting harmonic excitation.

Background technique

With the continuous improvement of the performance of permanent magnet materials and the continuous decline of prices, the use of permanent magnet materials in motors has become increasingly widespread. The use of permanent magnet materials brings many advantages to the motor: high power density, small size, light weight, high efficiency, brushless, simple structure, high reliability, and flexible structure. The research on permanent magnet motors has been a hot spot in the field of motor research for many years. Therefore, all countries in the world have invested a lot of manpower, material resources and financial resources in the research and development of permanent magnet motors, and many motors with new structures have appeared. However, there are still some difficulties in the research and application of permanent magnet motors, which need to be further deepened.

There are many types of permanent magnet motors that can operate not only as generators, but also as electric motors. As a generator, the permanent magnet synchronous generator adopts permanent magnet excitation. When the load causes the armature current to change or the speed to change, it cannot adjust the excitation magnetomotive force by adjusting the excitation current like ordinary electric excitation generators, so that the generator The terminal voltage changes accordingly, affecting the normal operation of the load.

For motors, in some high-performance applications, a wide range of speed regulation is required. In the high-speed section, constant power is used for speed regulation. At this time, it is necessary to weaken the magnetic field for speed regulation, but the excitation magnetic field of the permanent magnet motor cannot be adjusted.

It can be seen that the adjustment of the excitation magnetic field of permanent magnet motors is an important issue in the application of permanent magnet motors. Researching and solving the problem of magnetic field adjustment of permanent magnet motors is of great significance for the improvement of the performance of permanent magnet motors and the widespread promotion and use of permanent magnet motors.

In the hybrid excitation permanent magnet motor, there are both permanent magnet poles and excitation windings, and two magnetic potential sources exist at the same time, which combines the advantages of convenient field adjustment of electric excitation synchronous motors, high efficiency and large torque/mass ratio of permanent magnet synchronous motors. Therefore, the hybrid excitation motor has become a hot topic. Scholars from various countries have conducted in-depth research on it and proposed many excitation schemes.

The University of Wisconsin in the United States proposed a hybrid excitation permanent magnet motor. The stator winding is similar to that of an ordinary permanent magnet machine. There are permanent magnets and electric excitation on the rotor respectively. The permanent magnet poles account for the majority, and the electric excitation poles provide a small part of the magnetic field. Variations in the balancing air gap magnetic field. The motor magnetic circuit of this solution is similar to the traditional motor, and the structure is simple, but the rotor electric excitation winding and the external still need slip rings and brushes, which cannot be brushless, resulting in a large amount of maintenance work for the motor.

Contents of the invention

The object of the present invention is to address the above-mentioned deficiencies in the prior art, to provide a hybrid excitation permanent magnet motor using harmonic excitation that does not require brushes and slip rings, and can adjust the magnetic field in the motor on the stator.

The technical scheme of the present invention is realized like this: adopt the hybrid excitation permanent magnet motor of harmonic excitation, comprise a casing 1, the stator that is made up of stator core 2, stator winding 3 is housed in casing 1 and is made up of permanent magnet magnetic pole 4, The rotor composed of ferromagnetic poles 5, rotating shaft 6, rotor core 7, and rotor winding 8, the stator winding 3 is composed of stator main winding 11 and stator harmonic excitation winding 12, distributed in the slot 9 opened on the stator core 2 along the circumferential direction The rotor core 7 is provided with a permanent magnetic pole 4 and a ferromagnetic pole 5 , and a rotor winding 8 is arranged on the ferromagnetic pole 5 . The rotor winding 8 is composed of a rotor excitation winding 13 and a rotor harmonic winding 14 .

The stator main winding 11 can be arranged arbitrarily, and can be a three-phase winding, or a single-phase or multi-phase winding.

The stator harmonic excitation winding 12 can be arranged arbitrarily, and can be a three-phase winding, or a single-phase or multi-phase winding.

The rotor excitation winding 13 may be a concentrated winding or a distributed winding.

The rotor harmonic winding 14 can be arranged arbitrarily, and can be a three-phase winding, or a single-phase or multi-phase winding.

The number of the permanent magnet poles 4 and the ferromagnetic poles 5 of the rotor can be set arbitrarily, and the ratio of the two can be determined according to the voltage adjustment range.

The rotor is inside the stator or placed outside the stator.

The stator main winding 11 and the stator harmonic excitation winding 12 can be independent of each other, or one set can be used to realize the functions of two sets of windings.

The pole pitch of the rotor excitation winding 13 is the same as that of the stator main winding 11 .

The pole pitch of the rotor harmonic winding 14 is the same as that of the stator harmonic excitation winding 12 .

The rotor of the hybrid excitation permanent magnet motor adopting harmonic excitation of the present invention not only has permanent magnet poles 4, but also has ferromagnetic poles 5 arranged with rotor excitation windings 13 and rotor harmonic windings 14, and two sets of windings arranged on the stator : The stator main winding 11 and the stator harmonic excitation winding 12 can be independent of each other, or one set can be used to realize the functions of two sets of windings. The stator main winding 11 is used for electromechanical energy conversion, and the stator harmonic excitation winding 12 is used for excitation control. The number of pole pairs of the stator harmonic excitation winding 12 is greater than that of the stator main winding 11 . The number of pole pairs of the rotor is the same as the number of pole pairs of the stator main winding 11 , one part is permanent magnet poles 4 , and the other part is ferromagnetic poles 5 . In addition to the rotor excitation winding 13 with the same pole pitch as the permanent magnet pole 4, each ferromagnetic pole 5 is also equipped with a rotor harmonic winding 13 with the same pole pitch as the stator harmonic excitation winding 12. Winding 14. The stator main winding 11 corresponds to the permanent magnet pole 4 and the ferromagnetic pole 5 to generate electromagnetic induction, which is equivalent to a synchronous generator with rotating magnetic poles; the stator harmonic excitation winding 12 corresponds to the rotor harmonic winding 14 to generate electric current The magnetic induction effect is equivalent to a synchronous generator with a rotating armature. The electromotive force induced by the rotor harmonic winding 14 is rectified by the rotary rectifier to obtain direct current, which provides direct current to the rotor excitation winding 13 on the ferromagnetic pole 5, and the adjustment of the current of the rotor excitation winding 13 can be realized by adjusting the current on the stator harmonic excitation winding 12 , so as to achieve the purpose of adjusting the voltage of the stator main winding 11.

Compared with the prior art, the hybrid excitation permanent magnet motor of the present invention has the following characteristics:

1. The motor does not need brushes and collector rings, with simple structure and high reliability.

2. The structure is similar to ordinary permanent magnet motors, which is conducive to the optimal design of magnetic circuit distribution and motor windings. The power density of the motor is high and the voltage distortion rate is low.

3. There is no axial magnetic circuit and additional air gap, the magnetic circuit is short, the magnetic flux leakage is small, the electric excitation is adjusted by the harmonic magnetic potential, the excitation loss is small, and the efficiency of the motor is high.

Description of drawings

Fig. 1 is an A-A sectional view of Fig. 2, which is a structural schematic diagram of a hybrid excitation permanent magnet motor using harmonic excitation. Among them, 1 is the casing, 2 is the stator core, 3 is the stator winding, 4 is the permanent magnetic pole, 5 is the ferromagnetic pole, 6 is the rotating shaft, 7 is the rotor core, 8 is the rotor winding, and 15 is the bearing.

Fig. 2 is a sectional view of the motor in Fig. 1, taking 8 poles as an example. Among them, 2 is the stator core, 3 is the stator winding, 4 is the permanent magnet pole, 5 is the ferromagnetic pole, 6 is the rotating shaft, 7 is the rotor core, 9 is the slot for winding on the stator core, and 10 is the winding slot on the rotor core groove.

Fig. 3 is a detailed diagram of part B-B in Fig. 2, for convenience, it is expanded into a straight line drawing. Among them, 2 is the stator core, 4 is the permanent magnet pole, 5 is the ferromagnetic pole, 7 is the rotor core, 9 is the slot for winding on the stator core, 10 is the slot for winding on the rotor core, 11 is the stator main winding, 12 13 is the rotor excitation winding, and 14 is the rotor harmonic excitation winding. The figure also draws the fundamental component of the magnetic field generated by the stator harmonic excitation winding DC.

Fig. 4 is a schematic diagram of a circuit in which the rotor harmonic winding is connected to the rotor excitation winding via a rectifier bridge.

Fig. 5 is another embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Example

As can be seen from Figures 1, 2, and 3, the hybrid excitation permanent magnet motor adopting harmonic excitation of the present invention includes a casing 1, and a stator core 2 is arranged in the casing 1, and the stator core 2 is slotted 9 along the circumferential direction. Stator winding 3 is arranged inside 9, and stator winding 3 is composed of stator main winding 11 and stator harmonic excitation winding 12. The casing 1 and the stator core 2 are fixed. A rotating shaft 6 is disposed inside the casing 1 , and the rotating shaft 6 is connected to the casing 1 through a bearing 15 . The rotor core 7 is arranged on the rotating shaft 6, the permanent magnet pole 4 and the ferromagnetic pole 5 are arranged on the rotor core 7, the ferromagnetic pole 5 is slotted 10, and the rotor winding 8 is arranged in the slot 10, and the rotor winding 8 is composed of the rotor excitation winding 13 and The rotor harmonic winding 14 is composed. The rotor winding 8 and the rotor core 7 can rotate together with the rotating shaft 6 in the stator core 2 .

The working principle of the present invention is: the rotating shaft 6 rotates at a synchronous speed, the rotor permanent magnet pole 4 establishes a magnetic field, and an electromotive force of a synchronous frequency is induced in the stator main winding 11, and the electromotive force cannot be adjusted when the rotational speed is constant. In order to adjust the electromotive force of the stator main winding 11 , a stator harmonic field winding 12 is arranged on the stator core 2 , and a rotor field winding 13 and a rotor harmonic field winding 14 are arranged on the rotor core 7 . The pole pitch of the rotor excitation winding 13 is the same as that of the stator main winding 11, and the pole pitch of the rotor harmonic winding 14 is the same as that of the stator harmonic excitation winding 12. Direct current is passed into the stator harmonic excitation winding 12 to generate a magnetic field that moves relative to the rotor harmonic winding 14, and the rotor harmonic winding 14 induces an electromotive force, which is rectified to output DC power required for excitation to the rotor excitation winding 13.

The electromagnetic interaction between the stator harmonic excitation winding 12 and the rotor harmonic winding 14 will be specifically described below with reference to FIG. 3 . Taking the situation that the pole pitch of the stator harmonic excitation winding 12 is 1/2 of the pole pitch of the stator main winding 11 as an example, the stator main winding 11 and the stator harmonic excitation winding 12 in Fig. as an example. The stator harmonic excitation winding 12 is supplied with a direct current, which will generate a magnetic field whose number of pole pairs is twice that of the number of pole pairs of the main stator winding 11. FIG. 3 shows a schematic diagram of the fundamental wave component in the magnetic field. This magnetic field does not move with respect to the stator core 2 and rotates at a synchronous speed with respect to the rotor core 7 . The frequency of the electromotive force induced in the rotor harmonic winding 13 is twice that of the fundamental induced electromotive force of the stator main winding 11 . When the rotation speed of the rotating shaft 6 is constant, changing the magnitude of the DC current of the stator harmonic excitation winding 12 can change the induced electromotive force of the rotor harmonic winding 14, realizing the transfer of excitation energy from the stator to the rotor without brushes and collector rings Purpose. The stator harmonic excitation winding 12 and the rotor harmonic winding 14 have the same pole pitch, and the pole pitch can be set arbitrarily, but the frequency of the induced electromotive force of the rotor harmonic winding 14 changes accordingly.

The AC electromotive force induced by the rotor harmonic winding 14 is rectified to obtain a direct current, and the direct current is passed into the rotor excitation winding 13 to realize excitation. The circuit diagram is shown in FIG. 4 .

The DC excitation current flows through the rotor excitation winding 13 to establish a static magnetic field relative to the rotor core 7. The magnetic field rotates at a synchronous speed relative to the stator core 2 and the stator main winding 11. The electromotive force of synchronous frequency is induced in the stator main winding 11, and the stator main winding 11 The winding 11 is connected with an external circuit to output energy to the outside. Taking the case where the pole pitch of the stator harmonic excitation winding 12 is 1/2 of the pole pitch of the stator main winding 11 as an example, the frequency of the induced electromotive force of the stator main winding 11 is 1/2 of the induced electromotive force of the rotor harmonic winding 14 . Changing the current of the rotor excitation winding 13 can change the induced electromotive force of the stator main winding 11, that is, through the current of the stator harmonic excitation winding 12, the electromotive force of the stator main winding 11 can be controlled, and the function of adjusting the voltage on the stator is realized. Brushes and slip rings. The rotor field winding 13 is only arranged on the ferromagnetic poles 5 and thus only serves to change the magnetic field below the ferromagnetic poles 5 . The magnetic field under the permanent magnet pole 4 will not change with the change of the stator harmonic excitation winding 14 current.

In order to improve the utilization rate of the magnetic field generated by the stator harmonic excitation winding 14 and increase the voltage regulation range, the structure shown in Figure 5 can be adopted. The figure shows the arrangement of a pair of rotor ferromagnetic poles 5, and the rest of the poles are arranged in the same way as the ferromagnetic poles. The poles 5 are the same, that is, each rotor pole is made into a ferromagnetic pole 5, and the ferromagnetic pole 5 is arranged with the rotor excitation winding 13 and the rotor harmonic winding 14 near the air gap, and the permanent magnet pole 4 is arranged at the bottom of the ferromagnetic pole 5.

When the invention is used as a generator, the stator main winding 11 is connected with the load; when it is used as a motor, the stator main winding 11 is connected with the drive power supply; the stator harmonic excitation winding 12 is connected with the excitation controller.

The rotor excitation winding 13 can be a concentrated winding or a distributed winding.

The rectification circuit can adopt bridge full-wave rectification or half-wave rectification.

Claims (8)

1. adopt the composite excitation permanent magnet motor of harmonic excitation, comprise a casing (1), it is characterized in that: be equipped with in the casing (1) by stator core (2), the stator that stator winding (3) is formed and by permanent magnetism magnetic pole (4), ferromagnetic magnetic pole (5), rotating shaft (6), rotor core (7), the rotor that rotor winding (8) is formed, stator winding (3) is made up of stator main winding (11) and stator harmonic excitation winding (12), be distributed in the groove of along the circumferential direction offering in the stator core (2) (9), be furnished with permanent magnetism magnetic pole (4) and ferromagnetic magnetic pole (5) in the rotor core (7), ferromagnetic magnetic pole (5) is gone up and is arranged rotor winding (8), rotor winding (8) is made up of rotor-exciting winding (13) and the humorous wave winding of rotor (14), the pole span of described rotor-exciting winding (13) is identical with the pole span of stator main winding (11), and the pole span of the humorous wave winding of described rotor (14) is identical with the pole span of stator harmonic excitation winding (12).

2. motor according to claim 1 is characterized in that: described stator main winding (11) is single-phase or polyphase windings.

3. motor according to claim 1 is characterized in that: described stator harmonic excitation winding (12) is single-phase or polyphase windings.

4. motor according to claim 1 is characterized in that: described rotor-exciting winding (13) can be to concentrate winding, also can be distributed winding.

5. motor according to claim 1 is characterized in that: the humorous wave winding of described rotor (14) is single-phase or polyphase windings.

6. motor according to claim 1 is characterized in that: described rotor permanent magnetism magnetic pole (4) can be provided with arbitrarily with the quantity of ferromagnetic magnetic pole (5), and both ratios can be determined according to the voltage-regulation scope.

7. motor according to claim 1 is characterized in that: described rotor is in stator or be positioned over outside the stator.

8. according to claim 2 or 3 described motors, it is characterized in that: described stator main winding (11) and stator harmonic excitation winding (12) can be separate, also can adopt a cover to realize the function of two cover windings.

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