KR20200099774A - Motor - Google Patents

Abstract

According to an embodiment of the present invention, provided is a motor which is easy for maintenance. The motor comprises: a stator including a stator sub-windings and a stator winding switch which controls an electric path, in which the stator sub-windings are formed, by one electric path of a first electric path in which the stator sub-windings are formed in series, and a second electric path in which the stator sub-windings are partially formed in parallel; and a rotor rotating in a first mode or a second mode with regard to the stator. The first mode is driven when the stator sub-windings become the first electric path by the stator winding switch, and the second mode is driven when the stator sub-windings become the second electric path by the stator winding switch.

Description

Electric motor {Motor}

The present invention relates to an electric motor and, more specifically, to an electric motor capable of operating in two modes.

An electric motor is a device that converts electrical energy into mechanical energy by using the force received by a conductor through which an electric current flows in a magnetic field. Among them, a synchronous motor (SM) refers to a motor in which a rotor can rotate at a constant speed in synchronization with a rotation field of a stator. The rotor of a synchronous motor has the advantage of being able to maintain a constant rotational speed even in a variable voltage environment.

Such synchronous motors include a permanent magnet synchronous motor (PMSM) and a wound rotor synchronous motor (WRSM).

A permanent magnet synchronous motor may use a permanent magnet to generate a rotor magnetic field (flux). Permanent magnet synchronous motors can provide a fixed speed in synchronization with the frequency of the power source despite fluctuations in load or voltage, and are widely used in various industrial and household applications due to their high efficiency and excellent performance of high torque density. have. In particular, a permanent magnet synchronous motor can be useful in that it can provide a fixed speed in synchronization with the main frequency within the range allowed by the design specifications of the motor. However, there are limitations in application because the unit cost of rare earth magnets used in permanent magnet synchronous motors is expensive.

On the other hand, the field-winding type synchronous motor has an advantage in terms of cost because it does not use a permanent magnet unlike a permanent magnet motor. A field winding type synchronous motor uses a field winding instead of a permanent magnet in the rotor, and the field winding receives DC current to generate the rotor magnetic field.

In general, when the field winding of the rotor receives electric current, it is necessary to use a brush or a slip-ring. Therefore, the field winding type synchronous motor is electrically operated by a brush and a slip ring. Mechanical loss occurs, magnetic field loss, and difficulty in maintenance management.

Furthermore, as shown in Fig. 1, the field winding type synchronous motor is damaged in the brush or slip ring where physical rotational contact occurs, and if the damage occurs, the motor must be stopped until the damaged part is repaired. There was a big problem because of the loss.

One technical problem to be solved by the present invention is to provide an electric motor that operates in two modes.

Another technical problem to be solved by the present invention is to provide a motor that can be driven even during failure of a part of the motor (slip ring, brush, DC source, etc.).

Another technical problem to be solved by the present invention is to provide an electric motor that is easy to maintain.

The technical problem to be solved by the present invention is not limited to the above.

An electric motor according to an embodiment of the present invention includes a stator sub-winding and an electric path formed by the stator sub-windings, a first electric path in which the stator sub-windings are in series, and a second electric path in which the stator sub-windings are partially parallel. A stator including a stator winding switch controlled by one of the electric paths; And a rotor rotating in a first mode or a second mode with respect to the stator, wherein the first mode is driven when the stator sub-windings become the first electric path by the stator winding switch, and the first mode The 2 mode may be driven when the stator sub-windings become the second electric path by the stator winding switch.

According to an embodiment, the rotor further includes a field winding for generating a rotor field, and the field winding is a rotor through a different energy source according to which mode of the first mode and the second mode is applied. Fields can be created.

According to an embodiment, in the case of the first mode, a power source that generates a rotor field in the rotor is contacted, and in the second mode, a power source that generates a rotor field in the rotor is non-contact. I can.

According to an embodiment, the rotor further includes a field winding for generating a rotor field, and in the first mode, the field winding receives an external DC current to generate a rotor field, and the second In the case of the mode, the field winding may generate a rotor field based on a sub harmonic generated by some current flowing through the stator sub windings.

According to an embodiment, the rotor is provided between a contact type supply unit connected to the field winding in a contact type and between the field winding and the contact type supply unit, and an external current controlling an electrical connection between the field winding and the contact type supply unit A switch may be further included, wherein in the first mode, the external current switch is controlled in an ON state, and in the second mode, the external current switch may be controlled in an OFF state.

According to an embodiment, the rotor is provided between the rectifier and the field winding, a harmonic field generating a harmonic current by the sub-harmonic, a rectifier that rectifies the harmonic current and provides it to the field winding, and Further comprising a harmonic current switch for controlling the electrical connection between the rectifier, in the case of the first mode, the harmonic current switch is controlled in an OFF state, in the case of the second mode, the harmonic current switch is in an ON state. Can be controlled.

According to an embodiment, the stator sub-windings are composed of at least four, and at least two of the stator sub-windings are in parallel in the second electric path, and a current flowing through the stator sub-windings forming the parallel May generate a sub-harmonic provided to the rotor in the second mode.

According to an embodiment, the stator sub-windings include a first stator sub-winding, a second stator sub-winding, a third stator sub-winding, and a fourth stator sub-winding, and the stator winding switch includes the first stator sub-winding And a first stator winding switch for controlling an electrical connection between the third stator sub winding, a third stator winding switch for controlling an electrical connection between the second stator sub winding and the fourth stator sub winding, and the third stator It may include a second stator winding switch for controlling an electrical connection between the sub-winding and the first stator winding switch and between the second stator sub-winding and the third stator winding switch.

According to an embodiment, in the case of the first mode, the second stator winding switch is in an ON state, the first and third stator winding switches are in an OFF state, and in the second mode, the second stator winding The switch may be in an OFF state, and the first and third stator winding switches may be in an ON state.

According to an embodiment, the control unit further comprises a control unit, wherein when an abnormality is detected while rotating the rotor in the first mode, the first mode is changed to the second mode, and the abnormality is removed. If so, the second mode may return to the first mode.

An electric motor according to an embodiment may operate in two modes.

The electric motor according to an exemplary embodiment may be capable of driving a part of the electric motor even during failure (repair).

The electric motor according to an embodiment may be easy to maintain.

1 is a view showing damage to a brush and a slip ring according to the prior art.
2 is a diagram for explaining the structure of an electric motor according to an embodiment of the present invention.
3 and 4 are diagrams for explaining a circuit configuration according to an operation mode of an electric motor according to an embodiment of the present invention.
5 and 6 are diagrams for explaining in detail a circuit configuration of stator sub-windings according to an operation mode of an electric motor according to an embodiment of the present invention.
7 is a view for explaining a switch control for mode switching of an electric motor according to an embodiment of the present invention.
8 is a view for explaining a driving simulation of an electric motor according to an embodiment of the present invention.
9 to 12 show simulations and actual experimental results when the electric motor according to an embodiment of the present invention operates in a first mode.
13 to 15 show simulations and actual experimental results when the electric motor according to an embodiment of the present invention operates in a second mode.
16 shows an example of manufacturing an electric motor according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical idea of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In the present specification, when a component is referred to as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. In addition, in the drawings, the shape and size are exaggerated for effective description of technical content.

In addition, in various embodiments of the present specification, terms such as first, second, and third are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another component. Accordingly, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. In addition, in the present specification,'and/or' is used to mean including at least one of the elements listed before and after.

In the specification, expressions in the singular include plural expressions unless the context clearly indicates otherwise. In addition, terms such as "include" or "have" are intended to designate the presence of features, numbers, steps, elements, or a combination of the features described in the specification, and one or more other features, numbers, steps, and configuration It is not to be understood as excluding the possibility of the presence or addition of elements or combinations thereof. In addition, in the present specification, "connection" is used to include both indirectly connecting a plurality of constituent elements and direct connecting.

Further, in the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

2 is a diagram for explaining the structure of an electric motor according to an embodiment of the present invention.

Referring to FIG. 2, an electric motor 1000 according to an embodiment of the present invention may include a stator 100 and a rotor 200. Each configuration is described in detail below.

Stator(100)

The stator 100 may be provided on one side of the rotor 200, for example, outside in the radial direction, and may provide rotational force to the rotor 200. To this end, the stator 100 may be created in a cylindrical shape including a hollow inside, and the rotor 200 may rotate while being inserted into the hollow of the stator 100.

According to an embodiment, the stator 100 may include a plurality of teeth 110 on which the main winding is seated. For example, the plurality of teeth 110 may be arranged in a circumferential direction inside the cylinder of the stator 100.

The stator 100 may include a stator winding 120 that generates a stator field so that the rotor 200 can rotate. The stator windings 120 may be grouped according to a phase of an applied current. For example, when three phases of A, B, and C are applied to the stator winding 120, the stator winding 120 includes a first stator winding 120A, a second stator winding 120B, and a third stator. It can be grouped into windings 120C.

In this case, each stator winding may be formed of sub stator windings. There is no limitation on the number of sub-stator windings, but for convenience of explanation, it is assumed that there are four sub-stator windings. In this case, the first stator winding 120A is the 1-1 st stator sub winding 120A1, the 1-2 st stator sub winding 120A2, the 1-3 st stator sub winding 120A3, and the 1-4 stator sub winding. It may be made of a winding 120A4. In the same way, the second stator winding 120B includes the 1-1 st stator sub winding 120B1, the 1-2 st stator sub winding 120B2, the 1-3 st stator sub winding 120B3, and the 1-4 stator sub winding. A winding 120B4 may be formed, and the third stator winding 120C includes the 1-1 stator sub winding 120C1, the 1-2 st stator sub winding 120C2, the 1-3 st stator sub winding 120C3 and It may be made of a 1-4 stator sub-winding 120C4.

Rotor(200)

The rotor 200 may rotate with respect to the stator 100 by a rotor field generated by the rotor 200 and a stator field generated by the stator 100.

More specifically, a plurality of teeth 211 are provided along the circumferential direction of the rotor 200, and the harmonic winding 220 and the field winding 240 may be formed on the plurality of teeth 211, respectively. A detailed description of the configuration of the rotor 200 will be described later.

According to an example, the number of poles of the stator winding 120 may be the same as the number of poles of the field winding 240. In addition, the number of poles of the harmonic winding 220 may be n times less than the number of poles of the stator winding 120. This is to cause the harmonic winding 220 to be excited by the sub harmonic generated in the stator winding 120.

The electric motor according to an embodiment of the present invention has been briefly described above with reference to FIG. 1. Hereinafter, a mode operation of an electric motor according to an embodiment of the present invention will be described with reference to FIGS. 3 to 7.

3 and 4 are diagrams for explaining a circuit configuration according to an operation mode of an electric motor according to an embodiment of the present invention, and FIGS. 5 and 6 are a stator according to an operation mode of an electric motor according to an embodiment of the present invention. A diagram for explaining the circuit configuration of the sub-windings in detail, and FIG. 7 is a diagram for explaining a switch control for mode switching of an electric motor according to an embodiment of the present invention.

The electric motor according to an embodiment of the present invention may operate in one of a first mode and a second mode. In this case, the rotor field generated by the rotor 200 may be generated by different energy sources depending on whether the first mode or the second mode is used. For example, in the first mode, the rotor field may be generated by an energy source supplied in a contact manner, for example, a DC power source contacted with a brush, and in the second mode, the rotor field is non- The energy source supplied in a contact manner, for example, may be generated by a sub-harmonic by a stator winding.

Switches may be provided in the stator 100 and the rotor 200 to implement the first mode or the second mode. Hereinafter, a stator winding switch provided in the stator 100 will be described first.

An electric motor according to an embodiment is provided between the stator sub-windings, and controls the electric path by the stator sub-windings as a first electric path (applied to the first mode) or a second electric path (applied to the second mode). It may include a stator winding switch.

In this case, the first electric path may be defined as a case where the stator sub-windings provide an electric path only in series, and the second electric path may be defined as a case where the stator sub-windings provide electric paths in series and parallel.

5 and 6, the stator winding switch is provided between the 1-1 st stator sub winding 120A1 and the 1-3 st stator sub winding 120A3, and the 1-1 st stator sub winding 120A1 and The 1-1 stator winding switch 410A for controlling the electrical connection between the 1-3 st stator sub-winding 120A3, between the 1-2 st stator sub-winding 120A2 and the 1-4 stator sub-winding 120A4 Provided in, the 1-3 stator winding switch 430A for controlling the electrical connection between the 1-2 stator sub-winding 120A2 and the 1-4 stator sub-winding 120A4, the 1-3 stator sub-winding ( 120A3) and the 1-1 stator winding switch 410A, and the 1-2 stator winding switch for controlling the electrical connection between the 1-2 st stator winding switch (120A2) and the 1-3 stator winding switch 420A (420A) may be included.

The first stator winding switches 410A, 420A, and 430A provided between the first stator sub-windings 120A have been described as the center, but as shown in FIGS. 5 and 6, the second stator sub-windings 120B It goes without saying that the stator winding switches 410B, 420B and 430B and the stator winding switches 410C, 420C, and 430C may be provided between the three stator sub-windings 120C, respectively.

5 and 7, for driving in the first mode, a controller (not shown) may implement a first electric path by controlling each stator winding switch. For example, the controller may turn on the 1-2 stator winding switch 420A, the 2-2 stator winding switch 420B, and the 3-2 stator winding switch 420C, and turn off the rest of the switches. Accordingly, the stator sub windings can be electrically connected in series.

6 and 7, for driving in the second mode, the controller may implement a second electric path by controlling each stator winding switch. For example, the controller may turn off the 1-2 stator winding switch 420A, the 2-2 stator winding switch 420B, and the 3-2 stator winding switch 420C, and turn on the rest of the switches. Accordingly, of the first stator sub-windings to which the current of phase A is applied, the 1-2 st stator sub-winding 120A2 and the 1-3 st stator sub-winding 120A3 may be electrically connected in parallel.

The configuration of the stator for implementing the first mode or the second mode has been described above. Hereinafter, a configuration of a rotor for implementing the first mode or the second mode will be described.

3 and 4, the rotor according to an embodiment may include a contact type supply unit 310 receiving external direct current. The contact-type supply unit 310 may be, for example, a slip ring or a brush. The contact type supply unit 310 may be electrically connected to the field winding 240 so as to supply external direct current to the field winding 240. In this case, an external current switch 440 may be provided between the contact type supply unit 310 and the field winding 240.

The external current switch 440 may allow external direct current to be supplied to the field winding 240 in the ON state, and may block the external direct current from being supplied to the field winding 240 in the OFF state. Accordingly, the control unit can implement the first mode by turning on the external current switch 440 and implement the second mode by turning off the external current switch 440.

In addition, the rotor may further include a harmonic current switch 450 provided between the rectifier 230 and the field winding 240 to control electrical connection between the rectifier 230 and the field winding 240. Accordingly, the control unit may implement the first mode by turning off the harmonic current switch 450 and implement the second mode by turning the harmonic current switch 450 ON.

Hereinafter, an example of driving an electric motor according to an embodiment of the present invention will be described.

The controller may drive the electric motor 1000 according to an embodiment in the first mode. To this end, the control unit may control the stator winding switch as described with reference to FIGS. 5 and 7 so that the stator sub-windings are electrically connected in series as shown in FIG. 3. That is, the controller may turn on the 1-2 stator winding switch 420A, the 2-2 stator winding switch 420B, and the 3-2 stator winding switch 420C, and turn off the rest of the switches. In addition, the controller may turn off the harmonic current switch 450 and turn on the external current switch 440 as shown in the lower part of FIG. 3.

In this case, rotation torque is generated by the interaction between the stator field generated by the stator winding 120 and the rotor field generated by the field winding 240 of the rotor 200.

Meanwhile, when an abnormality is detected while driving in the first mode, the controller may change the mode from the first mode to the second mode. For example, when a certain part is damaged, it may be determined that the rotor fails to rotate at the expected rotation speed. To this end, the control unit may continuously detect the rotational speed of the rotor through the encoder.

If an abnormality is detected while driving in the first mode, the controller may turn off the supply of external direct current and turn off the current applied to the stator winding. After the part in which the abnormality is detected is separated for repair, the control unit may change the first mode to the second mode. That is, even during repair of abnormal parts, the electric motor can continuously rotate in the second mode state.

To this end, the controller may control the stator winding switch as described with reference to FIGS. 6 and 7 so that the stator sub-windings are electrically partially connected in parallel as shown in FIG. 4. That is, the control unit may turn off the 1-2 stator winding switch 420A, the 2-2 stator winding switch 420B, and the 3-2 stator winding switch 420C, and turn on the rest of the switches. In addition, the controller may turn on the harmonic current switch 450 and turn off the external current switch 440 as shown in the lower part of FIG. 4.

In this case, among the current flowing through the stator winding 120, the 1-1 st stator sub winding 120A1, the 1-4 stator sub winding 120A4, the 2-1 stator sub winding 120B1, and the 2-4 Current flowing through the stator sub-winding 120B4, the 3-1 stator sub-winding 120C1, and the 3-4 stator sub-winding 120C4 may generate a stator field.

In addition, the 1-2 stator sub-winding 120A2, the 1-3 stator sub-winding 120A3, the 2-2 stator sub-winding 120B2, and the 2-3 stator sub-winding are connected in parallel to receive the branched current. The winding 120B3, the 3-2 stator sub-winding 120C2, and the 3-3 stator sub-winding 120C3 may generate a sub harmonic.

The harmonic winding 220 of the rotor 200 may be excited by the sub harmonic. Accordingly, the harmonic winding 220 may generate a harmonic current. The generated harmonic current may be rectified by the rectifier 230. The rectified harmonic current may be supplied to the field winding 240. The field winding 240 may generate a rotor field based on the supplied current.

Accordingly, even in the second mode, rotation torque is generated by the interaction between the stator field generated by the stator winding 120 and the rotor field generated by the field winding 240 of the rotor 200.

Thereafter, the controller may return to the first mode again when the detected abnormality is resolved.

The electric motor according to an embodiment of the present invention has been described above with reference to FIGS. 1 to 7. Hereinafter, simulation and actual experiment results according to an embodiment of the present invention will be described with reference to FIGS. 8 to 15. For reference, for the experiment, a simulation was conducted based on a motor having the number of poles and teeth as shown in FIG. 1, and a motor manufactured based on the motor having the number of poles and teeth shown in FIG. 16) The actual experiment was conducted.

8 is a view for explaining a driving simulation of an electric motor according to an embodiment of the present invention.

The MMF during operation in the first mode is indicated by a purple line. In addition, the MMF when operating in the second mode is displayed in black. In particular, referring to the second mode part, it was confirmed that the MMF of the same size as the first mode was generated in the stator winding regions 120A1, 120B1, 120C1, 120A4, 120B4, and 120C4 in which the stator current was not branched. In contrast, in the stator winding regions 120A2, 120B2, 120C2, 120A3, 120B3, and 120C3 in which the stator current is branched in both the second mode, it can be seen that the MMF size is reduced compared to the first mode. It is interpreted that this is because some of the stator's current was used to generate the sub-harmonic.

9 to 12 show simulations and actual experimental results when the electric motor according to an embodiment of the present invention operates in a first mode.

9 and 10 show simulation results and actual experiment results when operating in the first mode, respectively. As shown in FIG. 9, the EMF according to the simulation could be confirmed as an actual experiment result as shown in FIG. 10.

11 and 12 show simulation results and actual experiment results when operating in the first mode, respectively. As shown in FIG. 11, the torque according to the simulation could be confirmed as an actual experiment result as shown in FIG. 12.

13 to 15 show simulations and actual experimental results when the electric motor according to an embodiment of the present invention operates in a second mode.

13 shows simulation results for each of the field currents rectified by the rectifier with the harmonic current and the harmonic current generated by the harmonic winding. It can be seen that a stable DC field current is applied to the field winding.

Referring to FIG. 14, it can be confirmed as a simulation result that torque is stably generated even when operating in the second mode. Referring to FIG. 15, it is also shown as an actual experiment result that torque is stably generated even when operating in the second mode. I can confirm.

As described above, the present invention has been described in detail using preferred embodiments, but the scope of the present invention is not limited to specific embodiments, and should be interpreted by the appended claims. In addition, those who have acquired ordinary knowledge in this technical field should understand that many modifications and variations can be made without departing from the scope of the present invention.

Claims (10)

The stator sub-windings and the electric path formed by the stator sub-windings are controlled by one of a first electric path in which the stator sub-windings are formed in series and a second electrical path in which the stator sub-windings are partially in parallel. A stator including a stator winding switch; And
Including a rotor rotating in a first mode or a second mode with respect to the stator,
The first mode is driven when the stator sub-windings become the first electric path by the stator winding switch, and the second mode is when the stator sub-windings become the second electric path by the stator winding switch. When the electric motor is driven. The method of claim 1,
The rotor further comprises a field winding generating a rotor field,
The electric motor for generating a rotor field through a different energy source according to which of the first mode and the second mode the field winding corresponds to. The method of claim 1,
In the case of the first mode, the rotor is in contact with a power source that creates a rotor field and
In the case of the second mode, an electric motor in non-contact with a power source that creates a rotor field in the rotor. The method of claim 1,
The rotor further comprises a field winding for generating a rotor field,
In the case of the first mode, the field winding receives an external DC current to generate a rotor field,
In the second mode, the field winding generates a rotor field based on a sub-harmonic generated by some current flowing through the stator sub-windings. The method of claim 4,
The rotor further comprises a contact-type supply part connected to the field winding in a contact manner, and an external current switch provided between the field winding and the contact-type supply part to control an electrical connection between the field winding and the contact-type supply part,
In the case of the first mode, the external current switch is controlled in an ON state, and in the second mode, the external current switch is controlled in an OFF state. The method of claim 4,
The rotor is provided between the field winding and a harmonic field generating a harmonic current by the sub-harmonic, a rectifier that rectifies the harmonic current and provides it to the field winding, and an electrical connection between the field winding and the rectifier Further comprising a harmonic current switch for controlling,
In the case of the first mode, the harmonic current switch is controlled in an OFF state, and in the second mode, the harmonic current switch is controlled in an ON state. The method of claim 1,
The stator sub-windings consist of at least 4,
In the second electric path, at least two of the stator sub-windings are in parallel,
A current flowing through the stator sub-windings forming the parallel generates a sub-harmonic provided to the rotor in the second mode. The method of claim 1,
The stator sub-windings include a first stator sub-winding, a second stator sub-winding, a third stator sub-winding and a fourth stator sub-winding,
The stator winding switch comprises a first stator winding switch for controlling an electrical connection between the first stator sub winding and the third stator sub winding, and an electrical connection between the second stator sub winding and the fourth stator sub winding. A third stator winding switch to control and a second stator winding switch for controlling electrical connection between the third stator sub winding and the first stator winding switch and between the second stator sub winding and the third stator winding switch Made, electric motor. The method of claim 8,
In the case of the first mode, the second stator winding switch is in an ON state, the first and third stator winding switches are in an OFF state,
In the second mode, the second stator winding switch is in an OFF state, and the first and third stator winding switches are in an ON state. The method of claim 1,
Further comprising a control unit,
The control unit changes the first mode to the second mode when an abnormality is detected while rotating the rotor in the first mode,
When the abnormality is removed, the electric motor to return the second mode to the first mode again.

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