CN210041606U

CN210041606U - Rotor structure of synchronous motor

Info

Publication number: CN210041606U
Application number: CN201921047498.1U
Authority: CN
Inventors: 蔡卓剑
Original assignee: Dawei Intelligent Technology (xiamen) Co Ltd
Current assignee: Dawei Intelligent Technology (xiamen) Co Ltd
Priority date: 2019-07-07
Filing date: 2019-07-07
Publication date: 2020-02-07
Anticipated expiration: 2029-07-07

Abstract

The utility model provides a synchronous machine's rotor structure, including rotor shaft, rotor core cover is on the rotor shaft, be equipped with excitation winding, supplementary excitation winding, one or more magnetic pole group on the rotor core, magnetic pole group includes first magnetic pole, second magnetic pole, first magnetic pole, second magnetic pole are installed on rotor core, the polarity of first magnetic pole and second magnetic pole is different, excitation winding is on rotor core, supplementary excitation winding is on rotor core, just supplementary excitation winding inlays in the first magnetic pole, the second magnetic pole outside. The utility model discloses synchronous machine mechanical structure is simple, need not do too big change alright realize the excitation to the rotor.

Description

Rotor structure of synchronous motor

Technical Field

The utility model relates to a rotor structure of motor especially relates to a synchronous machine's rotor structure and self-excitation method thereof, belongs to the electrical drive field.

Background

The synchronous motor is rapidly developed by the advantages of adjustable power factor, high operation efficiency and the like, and is widely applied to the fields of power generation, rail transit, electric automobiles, industrial automation and the like. Synchronous motors are mainly divided into an electrically excited synchronous motor and a permanent magnet synchronous motor.

The rotor excitation winding of the electrically excited synchronous motor needs to be connected to a rotor commutator, and then an external direct-current power supply is used for exciting the rotor through the commutator. However, the rotor commutator has a brush and slip ring structure, so that the operation reliability is low, the maintenance cost is high, sparks and dust are easily generated in the operation process, and the rotor commutator cannot be applied to application occasions with explosion-proof requirements.

The permanent magnet synchronous motor uses the permanent magnet to replace an excitation winding on the rotor to generate a magnetic field, a commutator is not needed, and the permanent magnet synchronous motor has the advantages of simple structure, easy maintenance and the like. However, in recent years, the price of rare earth permanent magnet materials is increased year by year due to limited supply of rare earth permanent magnet materials, and the manufacturing cost of the permanent magnet synchronous motor is increased. What is more troublesome is that the permanent magnet of the rotor of the permanent magnet synchronous motor can cause permanent demagnetization due to over-high temperature, vibration and other reasons, and the output power and the efficiency of the permanent magnet synchronous motor are influenced.

At present, there is a solution for improving the two conventional excitation methods, for example, a set of resolver device is additionally added to the original stator and rotor structure of the synchronous motor, and the excitation energy is injected into the rotor winding through a set of control circuit by using the resolver, thereby realizing the rotor excitation. The method omits a rotor commutator structure, does not need a permanent magnet, and can conveniently control the rotor exciting current. However, the scheme needs to change the stator and rotor structures of the synchronous motor, and needs to add an additional excitation power supply and a controller, which increases the complexity of the system and increases the overall cost.

Disclosure of Invention

The utility model provides a synchronous machine's rotor structure and self-excitation method thereof need not to do too big change to synchronous machine mechanical structure, alright realize the excitation to the rotor.

The utility model provides a synchronous machine's rotor structure, including rotor shaft, rotor core cover is on the rotor shaft, be equipped with excitation winding, supplementary excitation winding, one or more magnetic pole group on the rotor core, magnetic pole group includes first magnetic pole, second magnetic pole, first magnetic pole, second magnetic pole are installed on rotor core, the polarity of first magnetic pole and second magnetic pole is different, excitation winding is on rotor core, supplementary excitation winding is on rotor core, just supplementary excitation winding inlays in the first magnetic pole, the second magnetic pole outside.

Further, the rotor structure further comprises an excitation controller, the excitation winding and the auxiliary excitation winding are respectively and electrically connected with the excitation controller, and the excitation controller is installed at one end of the rotor core.

Furthermore, the excitation controller comprises a first connection end and a second connection end, the auxiliary excitation winding is electrically connected with the first connection end of the excitation controller, and the excitation winding is electrically connected with the second connection end of the excitation controller.

Still further, the excitation controller includes a power conversion device and a signal processing device.

Furthermore, the power conversion device is composed of a driving controller and a current control circuit.

Furthermore, the signal processing device is composed of a band-pass filter and a digital signal processor.

The utility model discloses still disclose the synchronous machine of using above-mentioned rotor structure, synchronous machine is salient pole motor or implicit expression motor, synchronous machine still includes stator structure, stator structure includes stator winding.

The utility model also discloses an above-mentioned synchronous machine's self-excitation method, including to pour into the mixed current that fundamental frequency electric current, high frequency electric current constitute in the stator winding.

Further, the high-frequency current contains given value information of the excitation current.

Further, the high frequency current frequency is not less than 5 times the fundamental frequency current frequency and not greater than 1/5 times the PWM carrier frequency.

Compared with the prior art, the utility model, following beneficial effect has:

1. the utility model generates rotor exciting current through the interaction of the stator winding and the rotor exciting winding and the auxiliary exciting winding, and eliminates the hidden troubles such as spark generation caused by the demagnetization of the permanent magnet and the operation of the commutator, without the need of the permanent magnet for rotor excitation or an external exciting power supply;

2. the utility model has very limited change to the rotor structure of the traditional synchronous motor, thereby conveniently realizing the upgrading and reconstruction of the existing synchronous motor and reducing the technical popularization difficulty;

3. the utility model discloses adopt the high frequency injection method on control mode, contained the information that the motor expects rotor exciting current size in the high frequency current of injection, rotor excitation controller obtains expecting exciting current through the high frequency current information that detects the response, carries out active control to rotor exciting current, realizes synchronous machine's torque and the regulation of rotational speed.

Drawings

Fig. 1 is a schematic sectional view of a rotor structure according to an embodiment of the present invention;

fig. 2 is a schematic view of a cross-sectional structure of an implicit 2-pole synchronous motor according to an embodiment of the present invention;

fig. 3 is a schematic cross-sectional structure diagram of a hidden 4-pole motor rotor according to an embodiment of the present invention;

fig. 4 is a schematic cross-sectional structure view of a rotor of a convex 2-pole motor according to an embodiment of the present invention;

fig. 5 is a schematic cross-sectional structure view of a rotor of a 4-pole motor according to an embodiment of the present invention;

FIG. 6 is a functional block diagram of an excitation controller;

fig. 7 is a schematic diagram of a stator-side variable frequency drive.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.

The embodiment of the utility model discloses synchronous machine's rotor structure, as shown in fig. 1-7, including rotor shaft 1, rotor core 2 cover is on rotor shaft 1, rotor core 2 is last to be equipped with excitation winding 23, supplementary excitation winding 24, one or more magnetic pole group, magnetic pole group includes first magnetic pole 21, second magnetic pole 22, first magnetic pole 21 is different with second magnetic pole 22's polarity, excitation winding 23 winding is on rotor core 2, supplementary excitation winding 24 winding is on rotor core 2, just supplementary excitation winding 24 inlays in the first magnetic pole 21, the 22 outsides of second magnetic pole.

As shown in fig. 1 to 7, the rotor structure further includes an excitation controller 3, the excitation winding 23 and the auxiliary excitation winding 24 are electrically connected to the excitation controller 3, respectively, and the excitation controller 3 is installed at one end of the rotor core 2.

Specifically, as shown in fig. 1 to 7, the excitation controller 3 includes a first connection end and a second connection end, the auxiliary excitation winding 23 is electrically connected to the first connection end of the excitation controller 3, and the excitation winding 23 is electrically connected to the second connection end of the excitation controller 3.

In particular, as shown in fig. 2, the synchronous motor using the above rotor structure according to the embodiment of the present invention is an implicit bipolar synchronous motor, and the synchronous motor further includes a stator structure, and the stator structure is provided with a stator winding 4. As shown in fig. 3, the magnetic pole groups of the rotor structure according to the embodiment of the present invention may also be 2 or more groups, forming an implicit multi-pole synchronous rotor structure; as shown in fig. 4 and 5, the rotor structure of the embodiment of the present invention may also adopt a convex 2-pole synchronous rotor structure or a convex multi-pole synchronous rotor structure. The stator winding 4 is connected with an external variable frequency drive.

Wherein, as shown in fig. 1-7, the embodiment of the present invention adds a set of auxiliary exciting winding 24 on the basis of the traditional exciting winding 23, and the auxiliary exciting winding 24 is embedded in the position of the magnetic pole, so that when the stator winding 4 generates current, the auxiliary exciting winding 24 generates induced potential due to electromagnetic induction. The field winding 23 and the auxiliary field winding 24 are connected to the field controller 3. As shown in fig. 1, which is a schematic view of a rotor structure with a non-salient pole structure, it can be seen from fig. 1 that an excitation controller 3 is installed at an end of the rotor, and since the excitation power of a synchronous motor is small, the controller has a simple structure and a small volume, does not occupy too much space at the end, and avoids special changes to a base of the motor; fig. 2 is a schematic diagram of a cross-sectional structure of a rotor winding, in which the auxiliary excitation windings 24 are connected in series or in parallel, the end of the auxiliary excitation winding 24 is connected to a first connection end of the excitation controller 3, and the end of the excitation winding 23 is connected to a second connection end of the excitation controller 3.

Specifically, as shown in fig. 6, the excitation controller 3 includes a power conversion device and a signal processing device.

Specifically, as shown in fig. 6, the power conversion apparatus is composed of a driving controller and a current control circuit.

Specifically, as shown in fig. 6, the signal processing device is composed of a band-pass filter and a digital signal processor.

Fig. 6 is a functional block diagram of the excitation controller, where Lf represents the excitation winding 23, Lx represents the auxiliary excitation winding 24, if represents the excitation current, and iref is the excitation current set value. As can be seen from the figure, the excitation winding 23 and the auxiliary excitation winding 24 are both connected with the current control circuit, and the induced electromotive force generated by the excitation winding and the auxiliary excitation winding is accurately controlled by the current control circuit to excite a basically constant direct current in the excitation winding. The auxiliary exciting winding 24 is connected with the signal processing device, a band-pass filter separates a high-frequency current signal from a fundamental frequency current signal, then the high-frequency current signal is demodulated in a digital signal processing part to finally obtain an exciting current given value iref, the exciting current given value iref is sent to the driving controller, and the driving controller controls the current control circuit to realize the adjustment of the exciting current in the exciting winding group 23, so that the self-excitation effect is achieved.

During operation, as shown in fig. 7, a high-frequency current signal is superimposed on the basis of the fundamental frequency current signal, and a rotor exciting current given value (digital quantity) is superimposed on the high-frequency current signal after signal modulation, and then is modulated by PWM to generate a driving pulse to control the on and off of the power device.

When the motor is in a stable operation state, the stator side variable frequency driver is controlled to inject a high-frequency current component into the stator winding, the frequency of the current component is more than 5 times of the fundamental frequency and less than 1/5 of the PWM carrier frequency, obviously, a rotating magnetic field generated by the high-frequency current is not synchronous with the rotating speed of the rotor, so that induced potentials can be generated in the excitation winding and the auxiliary excitation winding on the rotor side, and then under the action of the rotor excitation controller, required excitation current is generated to complete the excitation process of the rotor.

The above method is also effective when the motor is in acceleration, deceleration, or start-up and stop, but at this time, in addition to the magnetic field generated by the high-frequency current component, the magnetic field generated by the fundamental frequency current component induces electromotive forces in the field winding and the auxiliary field winding. Since the field winding controller can autonomously control the magnitude of the field current if, the field current can be kept stable.

The embodiment of the present invention is shown in fig. 7, and modulates the high-frequency current signal by the digital signal representing the given value of the exciting current, so that the obtained modulation signal contains the given value information of the exciting current, and the signal is superimposed on the high-frequency current component of the stator winding and finally reacts in the induced potential of the auxiliary exciting winding Lx. In the excitation controller, the above-mentioned modulation signal is extracted by a band-pass filter, and then demodulated in a digital signal processing part to finally obtain the excitation current given value iref. During the operation of the synchronous machine, the magnitude of the exciting current needs to be adjusted frequently, such as flux weakening control when rotating at a speed higher than the synchronous speed. In this case, the excitation current can be adjusted by a high-frequency current by changing the specified value of the excitation current in the stator-side driver.

The embodiment of the utility model provides a through stator winding and rotor excitation winding and supplementary excitation winding interact produce rotor exciting current, need not be used for the permanent magnet of rotor excitation or add the excitation power, eliminated hidden danger such as permanent magnet demagnetization and commutator operation production spark. And simultaneously, the embodiment of the utility model provides a rotor structure to traditional synchronous machine changes very limitedly, consequently can realize current synchronous machine's upgrading transformation very conveniently, reduces the popularization degree of difficulty of technique. Furthermore, the embodiment of the utility model provides an adopt the high frequency injection method on control mode, contained the information that the motor expects the rotor exciting current size in the high frequency current of injection, rotor excitation controller obtains expecting exciting current through the high frequency current information that detects the induction, carries out active control to rotor exciting current, realizes synchronous machine's torque and the regulation of rotational speed.

It should be finally noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, it should be understood by those skilled in the art that after reading the present specification, the technical personnel can still modify or equivalently replace the specific embodiments of the present invention, but these modifications or changes do not depart from the scope of the claims of the present application.

Claims

1. The utility model provides a synchronous machine's rotor structure, its characterized in that, includes rotor shaft, rotor core cover is on the rotor shaft, be equipped with excitation winding, supplementary excitation winding, one or more magnetic pole group on the rotor core, the magnetic pole group includes first magnetic pole, second magnetic pole, first magnetic pole, second magnetic pole are installed on rotor core, the polarity of first magnetic pole and second magnetic pole is different, excitation winding twines on rotor core, supplementary excitation winding twines on rotor core, just supplementary excitation winding inlays in the first magnetic pole, the second magnetic pole outside.

2. The rotor structure according to claim 1, further comprising an excitation controller, wherein the excitation winding and the auxiliary excitation winding are electrically connected to the excitation controller respectively, and the excitation controller is installed at one end of the rotor core.

3. The rotor structure according to claim 2, wherein the excitation controller includes a first connection end and a second connection end, the auxiliary excitation winding is electrically connected to the first connection end of the excitation controller, and the excitation winding is electrically connected to the second connection end of the excitation controller.

4. A rotor structure according to claim 2, characterised in that the excitation controller comprises power conversion means and signal processing means.

5. The rotor structure according to claim 4, wherein the power conversion means is composed of a drive controller and a current control circuit.

6. A rotor structure according to claim 4, characterized in that the signal processing means consist of a band-pass filter, a digital signal processor.