KR20080082781A - Motor and compressor including the same - Google Patents

Abstract

A motor and a compressor having the same are provided to reduce a manufacturing cost of the motor by implementing a starting characteristic of a general single-phase inductor motor without an inverter. A motor includes a rotor. The rotor is started by induced torque generated by supplying single-phase power to stator coils and rotated at synchronous speed after starting. The stator coils include a main winding connected to the single-phase power and an auxiliary winding connected to the single-phase power in parallel with the main winding. Capacitors connected in parallel are connected to the auxiliary winding in series. One of the capacitors is electrically connected to the auxiliary winding selectively by a switch(S).

Description

Motor and compressor including the same {Motor and compressor including the same}

1 is a cross-sectional view showing a rotor and a stator of a conventional induction motor;

2 is a conceptual diagram schematically showing a rotor and a stator coil of a conventional induction motor;

3 is a conceptual diagram schematically showing a rotor and stator coil circuit of a motor according to the present invention;

4 is an enlarged cross sectional view of a portion of the rotor shown in FIG. 3;

5A to 5C are cross-sectional views showing embodiments of the tip shape of the flux barrier shown in FIG. 3;

6 is an exploded perspective view of a rotor core of a motor according to the present invention;

7 is a plan view of the uppermost unit rotor core of the motor of one embodiment of the present invention;

8 is a plan view of a lowermost layer of a motor of one embodiment of the present invention, or a top rotor unit core of a motor of another embodiment of the present invention;

9 is a top view of a rotor of the motor of one embodiment of the present invention;

10 is a rotor top plan view of a motor of one embodiment of the present invention, or a rotor bottom plan view of a motor of another embodiment of the present invention;

11 is a perspective view showing only the upper end ring of the motor of one embodiment of the present invention;

12 is a perspective view showing only the lower end ring of the motor of one embodiment of the present invention or a perspective view showing only the upper end ring of the motor of another embodiment of the present invention;

13 is a graph showing a relationship between a starting torque and a capacitor of a motor according to the present invention;

14 is a circuit diagram schematically showing a part of the stator coil circuit when the load of the motor according to the present invention is large;

15 is a circuit diagram schematically showing a part of the stator coil circuit when the load of the motor according to the present invention is small.

** Explanation of symbols for main parts of drawings **

10: stator 20: rotor

121: slot 122: conductor bar

123: rotor core 124, 125, 126: unit rotor core

130: magnet 140: flux barrier

150, 151: end ring

The present invention relates to a motor, and more particularly, to a motor having improved efficiency by minimizing losses. In addition, the present invention relates to a motor that improves the starting torque performance and increases the efficiency of normal operation.

The present invention also relates to a motor applicable when the load is variable, and to a variable displacement compressor to which such a motor is applied.

In general, single phase induction motors are wound on the stator where the main coil and auxiliary coils are spaced 90 ° apart from each other, and the supply voltage is applied directly to the main coil and the auxiliary coil through capacitors and switches. This is because the main coil alone does not start even when a voltage is applied. Therefore, the rotor system is generated in the stator through the starting device such as the auxiliary coil so that the rotor can be started.

Such a starting device is classified into a divided phase starting type, a shading coil type, a capacitor starting type or a rebound starting type according to the type thereof.

An example of a single phase induction motor having such a starting device is a capacitor start type single phase induction motor shown in FIGS. 1 and 2.

1 shows a stator and a rotor of a typical single phase induction motor, and FIG. 2 shows a simplified circuit of the rotor and stator coils.

When only the main coil 12 is wound around the stator 10, only an alternating magnetic field is generated in the stator 10 so that the rotor 20 is not started. Accordingly, the auxiliary coil 14 is wound around the stator to generate a rotating magnetic field, and the rotor is started and rotated by the rotating magnetic field. That is, the starting torque is generated through this rotor field.

Here, the capacitor 15 serves to delay the phase of the current applied to the auxiliary coil 14 to generate starting torque through interaction with the main coil 12. Once started, the rotor maintains rotation even when the auxiliary coil is not powered when there is no load change. Therefore, the power supply does not need to be applied to the auxiliary coil when the engine is rotated more than a predetermined number of revolutions after starting. However, when the load is variable, since the starting torque is required, it is preferable that the auxiliary coil is always supplied with power through a capacitor.

Of course, in the case of a three-phase induction motor, even if only the main coil is wound on the stator, a rotation system is generated, and thus, the aforementioned auxiliary coil does not need to be wound on the stator. In other words, no separate starting device is required.

Such a single phase induction motor does not require an inverter configuration like a brushless DC (BLDC) motor or a reluctance motor, and has a merit of being excellent in price because it can be started using a single phase commercial power supply.

1 and 2, a general single phase induction motor will be described in detail.

The stator 10 is hollow and has a plurality of teeth 11 protruding radially inwardly at predetermined angular intervals along an inner circumferential surface thereof and the teeth so as to have polarities of N poles or S poles when a primary current is applied. (11) it comprises a main coil 12 wound around each.

Here, an insulator (not shown) is provided between the tooth 11 and the main coil 12 to perform an insulation function between the tooth and the main coil and to allow the main coil to be easily wound.

In addition, the stator 10 includes an auxiliary coil 14 which is wound at a predetermined angle with the main coil 12 to form a rotating magnetic field when a current is applied. Of course, the auxiliary coil is also wound around the tooth 11 through an insulator, and may be referred to as a stator coil or a coil through the main coil 12 and the auxiliary coil 14.

The coils 12 and 14 are connected to a single phase power source, and the main coil 12 and the auxiliary coil 14 are connected in parallel with each other. In addition, a capacitor 15 is connected in series to the auxiliary coil. Although not shown, the capacitor may be selectively connected to a power source through a switch.

In general, a squirrel cage rotor is used in the rotor 20, and the squirrel rotor is illustrated in FIGS. 1 and 2.

The rotor 20 is usually formed by stacking steel sheets having a plurality of slots 21 formed at predetermined angles along an outer circumference at a predetermined radial position in a center. In addition, the rotor includes a rod-shaped conductor bar 22 inserted into the slot 21 of the rotor core, and the rod-shaped conductor bar is usually made of copper or aluminum rod.

In addition, both ends of the cage rotor core are connected to an end ring (not shown, see FIGS. 11 to 12) to form an electrical short through the conductor bar, which is generally formed by aluminum die casting. That is, the conductor bar 22 and the end ring are integrally formed through aluminum die casting, and the end rings are respectively formed on the upper and lower portions of the rotor core.

On the other hand, the rotor 20 has a shaft hole 24 is formed in the center. In the shaft hole, a rotation shaft (not shown) for transmitting the rotational force of the rotor to the outside is press-fitted so that the rotor and the rotation shaft are integrally rotated.

When the power is applied to the coil, the single phase induction motor generates an induction current in the conductor bar 22 and rotates by the induction torque generated through the induction current. In this case, however, a loss occurs in the conductor bar 22, which is called a conductor bar loss. Therefore, there is a certain limit to improve the efficiency of the motor in a motor of a constant size through the loss of the conductor bar. Therefore, there is a problem that cannot use such a single-phase induction motor as a motor that must satisfy high efficiency.

In addition, there is a problem that the temperature of the rotor 20 due to the loss of the conductor bar rises, and the change of the loss caused by the temperature change is large. In particular, this conductor bar loss becomes larger with increasing temperature. Therefore, there is a certain limit in improving the efficiency of the motor at high temperature.

On the other hand, the single-phase induction motor must always be operated at a speed less than the synchronous speed in order to generate the induction torque. This is because in theory, in a single-phase induction motor, torque is zero at synchronous speed, and the lower the rotation speed, the greater the torque.

Therefore, in the single-phase induction motor, the speed of the rotating shaft, that is, the speed of the motor changes as the load of the motor, that is, the load on the rotating shaft changes, which causes a problem in that the control of the motor according to the load variation is not easy.

An object of the present invention is to solve the problems of the above-described single-phase induction motor.

More specifically, it is an object of the present invention to improve the efficiency of the motor, and in particular to provide a motor that maximizes the efficiency during normal operation by operating at a synchronous speed during normal operation.

In addition, an object of the present invention is to provide a motor that is easy to control by always operating at a synchronous speed even if the load of the motor changes during normal operation.

In addition, an object of the present invention is to provide a motor that maximizes efficiency at high temperatures.

In addition, an object of the present invention is to provide a motor that can reduce the manufacturing cost by having the starting characteristics of a general single-phase induction motor without using an inverter configuration.

In addition, an object of the present invention is to provide a compressor that can increase the efficiency and facilitate variable capacity operation by applying the motor.

In order to achieve the above object, the present invention provides a motor in which a rotor is started by induction torque formed by supplying power to a coil provided in a stator, the rotor comprising: a rotor core; A conductor bar formed along the circumferential direction at an inner outer side of the rotor core to form an induced current; A flux barrier formed inside the rotor core to interrupt a flow of magnetic flux and generating a reluctance torque; And it is provided to generate a magnetic flux inside the rotor core to provide a motor comprising a magnet for generating a magnetic torque.

Here, the rotor is started by the induction torque by the conductor bar, and after starting, the rotor is rotated by the reluctance torque by the flux barrier and the magnetic torque by the magnet. And the rotor rotates at a synchronous speed by the reluctance torque and the magnetic torque after starting.

That is, the motor according to the present invention has the starting characteristic of a general induction motor at the start of the rotor, and has the rotation characteristic of the synchronous motor after starting. In addition, since the motor according to the present invention rotates at a synchronous speed by the reluctance torque and the magnetic torque during normal operation after starting, the motor has high efficiency.

In this case, the induction torque is formed by a rotating magnetic field formed in the stator and an induction current formed in the rotor. Therefore, the three-phase power supply does not necessarily need to be supplied to the coil. That is, single phase power may be supplied as in a typical single phase induction motor.

On the other hand, in the case where the single-phase power is supplied to the coil, the coil preferably comprises a main winding and an auxiliary winding for starting. Of course, the configuration for such a starting characteristic can be variously modified, but in the present invention will be described limited to the induction motor of the capacitor start type for convenience.

On the other hand, when the induction motor of the capacitor start type is applied to the present invention, the main winding and the auxiliary winding are connected in parallel to each other in a single-phase power source. And a capacitor is connected in series with the auxiliary winding.

The flux barrier is preferably arranged to form at least two or more even poles in the rotor. Through this flux barrier, the rotor, the q axis is formed in the radial direction from the center of the rotor but the flux flow is interrupted by the flux barrier; And the d-axis is formed in the radial direction from the center of the rotor, the flow of magnetic flux is not hindered.

Here, two poles may be formed in the rotor, in which case the q-axis and the d-side are spatially orthogonal to each other. The flux barrier is preferably formed to be symmetrical about the q axis.

In addition, the flux barrier is preferably formed such that the distance from the axis orthogonal to the q-axis orthogonal to the center of the rotor toward or away from the center toward both ends. This is to increase the reluctance torque further by increasing the proportion of the flux barrier in the whole stator core. In addition, in the same context, it is preferable that the flux barrier forming each pole is formed of at least two layers.

In addition, the flux barrier forming each layer may be continuously formed, and the length of the flux barrier formed inside the rotor may be longer than the length of the flux barrier formed outside.

On the other hand, the magnet may be inserted into a portion of the flux barrier, the magnet may be provided with at least two or more in the longitudinal direction of the flux barrier. Of course, at least two magnets may be provided in the longitudinal direction of the rotor. In this case, the magnet is preferably made of unit magnets of the same shape.

The flux barrier is preferably provided with a stepped portion to determine a position at which the magnet is inserted.

On the other hand, the line formed by both ends of the magnets inserted into each layer is preferably parallel to the q-axis. That is, the largest magnetic flux is formed based on the q axis by the arrangement of the magnet tips, and the magnetic flux form of the magnetic fluxes formed by the magnets may be formed into a square wave shape instead of a sine wave shape.

This arrangement of magnets makes it possible to generate a larger form of magnetic torque about the q axis and to increase the width of the end ring as described below, thereby reducing the loss in the end ring. .

In addition, it is preferable that the radial width of the conductor bar provided within an angle formed between the both ends of the plus barrier and the center of the rotor provided at the outermost part of the flux barrier among the conductor bars is smaller than the radial width of the other conductor bars. Do. This is because the larger the radial width of the conductor bar is, the smaller the portion that magnetic flux can flow in the portion, and thus, the magnetic flux saturation occurs early and the reluctance torque becomes smaller.

In order to minimize leakage of magnetic flux between the flux barrier and the conductor bar, an end of the flux barrier is preferably formed to face the conductor bar in close proximity. In addition, the width of the end of the flux barrier is preferably formed to be smaller than the width at the other portion. This is because, when forming the conductor bar and the end ring through aluminum die casting, the aluminum melt may be introduced into the flux barrier by pressure.

On the other hand, in order to achieve the above object, the present invention is a motor in which the rotor is started by the induction torque is formed by supplying power to the coil provided in the stator, the rotor, the rotor core; A conductor bar having a plurality of conductor bars formed along the circumferential direction of the inner core of the rotor core to form an induced current; A magnet provided to generate magnetic flux inside the rotor core to generate magnetic torque; And provided to the upper and lower portions of the rotor core so as not to interfere with the magnet, and provides a motor comprising an end ring forming a short circuit with the plurality of conductor bars.

In addition, the present invention is a motor in which the rotor is started by the induction torque is formed by supplying power to the coil provided in the stator, the rotor, the rotor core; A conductor bar having a plurality of conductor bars formed along the circumferential direction of the inner core of the rotor core to form an induced current; A flux barrier formed inside the rotor core to interrupt a flow of magnetic flux to generate reluctance torque; And provided on the upper and lower portions of the rotor core so as not to interfere with the flux barrier, it provides a motor comprising an end ring forming a short circuit with the plurality of conductor bars.

That is, the motor according to the present invention may have only one of a flux barrier and a magnet, and both may have. In either case, however, the end ring is preferably provided so as not to interfere with the flux barrier and / or the magnet.

In addition, the present invention provides a compressor and a control method of the compressor to which the above-described motor is applied.

Here, the motor is applied to the compressor, the rotor is started by the induction torque formed by supplying a single-phase power to the coil provided in the stator, and rotates at a synchronous speed after starting, the coil is connected to the main winding connected to the single-phase power It may be a motor comprising an auxiliary winding connected to the single-phase power source in parallel with the main winding, the capacitor is connected in parallel to each other in series.

Hereinafter, a motor according to the present invention will be described in detail with reference to FIGS. 3 to 15. In addition, for convenience of description, an inner type motor in which the rotor is rotatable inside the stator is taken as an example. However, the motor according to the present invention is not necessarily limited to an inner type motor.

Since the motor according to the present invention is a motor in which the rotor is started by the induction torque, it can have the same configuration of a conventional general induction motor. That is, as shown in Figure 3, as the configuration of the induction motor, the slot 121 and the conductor bar 122 formed in the rotor 130, and the stator coils 112, 114 (hereinafter 'coil') for the rotation of the motor And the capacitor 115 may be included. Therefore, detailed description is abbreviate | omitted about the overlapping structure.

On the other hand, the motor according to the present invention may be formed to include a flux barrier 140 (flux barrier, magnetic flux barrier) is formed to interfere with the flow of the magnetic flux inside the rotor core to generate a reluctance torque. In addition, the motor according to the present invention may be provided to generate a magnetic flux inside the rotor core may include a magnet 130 for generating a magnetic torque.

Therefore, according to the present invention, it is possible to provide a motor which is started in accordance with the characteristics of the induction motor at the start, and is driven in accordance with the characteristics of the synchronous motor in the normal operation. In other words, the rotor can be rotated at a synchronous speed by the reluctance torque and the magnetic torque after starting. Therefore, according to the present invention, unlike a general synchronous motor, it does not require complicated and expensive configurations such as an inverter for starting.

Hereinafter, the principle in which reluctance torque and magnetic torque are generated in the motor according to the present invention will be described in detail with reference to FIG. 3.

First, reluctance torque will be described in detail.

As shown in FIG. 3, a flux barrier is formed along the q axis. Here, the flux barrier is formed by removing a part of the rotor core 123 that is a magnetic material. That is, it is possible to form an air layer through the flux barrier, and may also be filled with a nonmagnetic material, for example, resin.

Here, when a current is applied to the coil to form a magnetic pole, magnetic flux is also formed on the rotor. However, along the q-axis in which the flux barrier 140 is formed, reluctance is very high due to the flux barrier. On the contrary, in this case, the reluctance is formed very small along the d-axis where the flux barrier 140 is not formed.

Therefore, the rotor rotates in a direction that minimizes the difference in reluctance in the q-axis and d-axis directions, and this rotation is called reluctance torque. In addition, the larger the difference in reluctance, the larger the reluctance torque can be obtained.

Meanwhile, as shown in FIG. 3, the magnet 130 may be further included in the motor according to the present invention. Here, if a current is applied to the coil to form a magnetic pole of the N pole, the magnet may be magnetized to become the S pole. That is, in the position of the rotor shown in Fig. 3, the reluctance in the q-axis direction becomes smaller due to the cancellation of the magnetic flux due to the stator and the magnetic flux due to the magnet. Therefore, the reluctance difference in the q-axis direction and the d-axis direction can be made larger than in the case where there is no magnet. Therefore, it is possible to obtain greater reluctance torque than without the magnet.

In addition, the magnet itself generates magnetic torque by interaction with the stator. That is, magnetic current is generated by flowing current in the coil, and magnetic torque is generated by the interaction between the magnetic pole of the stator and the magnetic pole of the magnet due to the position of the magnet according to the position of the rotor.

Therefore, since the motor according to the present invention rotates synchronously by the reluctance torque and the magnetic torque after starting, very high efficiency can be obtained in the steady state operation. This means that when the size of the motor is the same and the intensity of the applied current is the same, a very high efficiency can be obtained in the motor according to the present invention compared to a general induction motor.

Hereinafter, the rotor configuration of the motor according to the present invention will be described in detail with reference to FIGS. 3 to 5.

First, the rotor 120 includes a rotor core 123 that forms a basis, and a flux barrier 140 formed on the rotor, more specifically, the rotor core 123.

It is formed in the radial direction from the center of the rotor through the flux barrier 140 to form a q-axis to prevent the flow of magnetic flux. And the d-axis is formed in the radial direction from the center of the rotor does not interfere with the flow of magnetic flux.

Here, the flux barrier may be arranged to form at least two or more even poles along the circumferential direction of the rotor, which is illustrated in FIG. 3. That is, when the flux barrier is arranged to form two poles, as illustrated in FIG. 3, the q-axis and the d-axis are spatially orthogonal to each other. In addition, when the flux barrier is arranged to form four poles, the q-axis and the d-axis are spatially at an angle of 45 degrees although not shown.

Meanwhile, as shown in FIG. 3, the flux barrier 140 is preferably formed to be symmetrical about the q axis. This is to prevent the noise or vibration caused by the deviation of the reluctance torque by causing the reluctance torque to be symmetrical about the q axis.

In addition, the flux barrier 140 is preferably formed of at least two layers. That is, at least two layers of flux barriers are preferably formed on each of the upper and lower half surfaces of the rotor shown in FIG. 3. This is to increase the ratio of the flux barrier 140 of the rotor core 123 in the q axis direction to further increase the reluctance in the q axis direction.

In addition, for the same reason, the flux barrier 140 may be formed such that an interval between the axis perpendicular to the q axis and the distance from or near to the center of the rotor 120 increases from the center to both ends thereof. In other words, as shown in FIG. 3, the flux barrier 140 is not formed to be parallel to the d axis, but is formed to be convex up or down based on the d axis. The flux barrier shape may be formed in an angular shape, or may be formed in an arc shape.

In addition, as shown in FIG. 3, the longer the length of the flux barrier 140 formed in the center of the rotor, that is, the inner side of the rotor, the longer the flux barrier is. This is for further increasing the reluctance in the q axis direction.

In addition, the radial width of the conductor bar 122 provided within the angle α formed between the both ends of the plus barrier and the center of the rotor provided at the outermost of the flux barrier 140 is the radial width of the other conductor bar. Smaller is preferred.

Because, as shown in FIG. 3, when the radial width of the conductor bar 122 provided in the angle α is increased, the distance between the conductor bar 122 and the flux barrier 140 becomes very narrow. Therefore, there is a high possibility of leakage magnetic flux due to the magnetic flux saturation in the d-axis direction. That is, it is preferable to reduce the radial width of the conductor bar 122 provided in the angle α so as to sufficiently secure such a gap.

On the other hand, as shown in Figures 4 to 5 end of the flux barrier 140 is preferably formed to face close to the slot 121. That is, the distance between the end of the flux barrier 140 and the slot 121 is preferably minimized. This is to minimize leakage of the magnetic flux formed along the d axis through the gap. In other words, if the magnetic flux leaks through the gap, the difference in reluctance in the q-axis and the d-axis direction decreases.

However, the gap formed between the end of the flux barrier 140 and the slot 121, that is, the gap formed between the end of the flux barrier 140 and the conductor bar 122 formed in the slot 121. There is a limit to the reduction. This is because when the conductor bar 122 is formed in the slot 121 through aluminum die casting or the like, the gap portion may be blown out by pressure, and aluminum melt may flow into the flux barrier 140.

Therefore, in order to reduce this concern and further reduce the gap, the width of the tip of the flux barrier 140 is preferably formed to be smaller than the width at other portions. Embodiments of this type are shown in FIGS. 5A-5C.

That is, through these embodiments, the length of the flux barrier 140 facing the slot 121 may be minimized, and thus the gap may be reduced by minimizing a portion that may be exploded by pressure. .

On the other hand, the motor according to the present invention comprises a magnet 130 is provided to generate a magnetic flux inside the rotor core to generate a magnetic torque.

Here, the magnet 130 may be inserted into a portion of the flux barrier 140 as shown in FIGS. 3 and 4. Of course, the magnets 130 may be inserted into all of the flux barriers 140 of each layer, and the magnets 130 may not be inserted into the flux barriers 140 of a specific layer.

On the other hand, the flux barrier 140 is preferably formed continuously in the longitudinal direction, the magnet 130 is preferably provided with at least two or more in the longitudinal direction of the flux barrier on one continuous flux barrier. This is because there is a lot of difficulty in forming a single magnet to match the shape of the flux barrier, it is possible to minimize the leakage flux generated in the magnet itself through a plurality of magnets.

For the same reason, it is preferable that at least two magnets are provided in the longitudinal direction of the rotor 120, that is, in the height direction of the rotor 120.

Due to these features, the magnet 130 may be formed of unit magnets having the same shape, for example, rod magnets. Therefore, there is an advantage of easy manufacturing by reducing the cost of magnet formation and minimizing the number of parts.

In addition, in order to determine a position where the magnet 130 is inserted into the flux barrier 140, a predetermined portion is preferably formed in the flux barrier. That is, the step portion 141 may be formed on the flux barrier 140 as illustrated in FIGS. 5B and 7 so that the insertion position of the magnet 130 may be determined. This seat will also function to prevent the magnet from flowing.

Hereinafter, a manufacturing method of a motor, in particular, a manufacturing method of a rotor according to the present invention will be described in detail with reference to FIGS. 6 to 12.

First, according to one embodiment of the motor according to the present invention, as shown in FIG. 6, the rotor core 123 may include three different types of unit rotor cores 124, 125, and 126. Of course, the motor in this form would be preferred for a direct drive motor, that is to say, when positioned in the state shown in FIG.

That is, the rotor core 123 is formed by stacking unit rotor cores formed by punching out, and these unit cores may be formed in three forms.

First, as described above, the unit core 125 constituting the middle portions of the rotor core 123, the slot 121 for forming the conductor bar, the shaft hole 128 for coupling with the rotating shaft, and the flux barrier 140 are all Can be formed.

6 and 8, only the shaft hole 128 and the slot 121 may be formed in the unit core 126 forming the lowermost portion of the rotor core 123. That is, no flux barrier is formed in the unit core 126. Therefore, even if a magnet is inserted into a portion of the flux barrier 140 of the unit cores 124 and 125, the magnet is prevented from falling out due to the unit core 126.

6 and 7, the unit core 124 forming the uppermost portion of the rotor core 123 is formed with a shaft hole 128, a slot 121, and a flux barrier 140. However, in this case, the flux barrier 140 is preferably formed only a minimum for the magnet is inserted. This is because of the relationship with the end ring described later.

Therefore, it is possible to insert the magnet into the flux barrier even after laminating the rotor core in the form shown in FIG. 6 and forming the end ring through aluminum die casting. In addition, even if there is no configuration to prevent the scattering of the magnet separately, if the motor is positioned in the form shown in Figure 6, the magnet is not scattered due to the interaction between the magnets and the inside of the rotor core.

Top and bottom views of this type of rotor core are shown in FIGS. 9 and 10, respectively. That is, according to the rotor core of this type, the end ring 151 formed at least under the rotor core can form an annular end ring of the general type as shown in FIG.

In other words, the rotor of the present form can be summarized as a rotor in which a magnet is inserted after the end ring is formed.

The general annular end ring may be formed to cover all portions except the shaft hole 128 on the top or bottom surface of the rotor core 123. As the height and width of the end ring increase, the loss through the end ring can be minimized. In other words, as with the loss of the conductor bar, the loss generated in the end ring can be minimized.

However, increasing the height of the end ring has a certain limitation due to the problem that the size of the motor increases. Therefore, it is more desirable to increase the thickness in the width direction of the end ring in order to minimize the loss due to the end ring.

Meanwhile, the uppermost unit core 124 illustrated in FIG. 6 may be replaced with the lowermost unit core 126 illustrated in FIG. 8. That is, the uppermost unit core and the lowermost unit core may be formed of the unit core 126 illustrated in FIG. 8. This form can be said to be another form of the motor according to the present invention.

In this type, the bottom unit core 126 and the middle unit core 125 are stacked first, and then the magnet is inserted into the flux barrier. The uppermost unit core (in this case, the same as the lowermost unit core) is laminated. Then, the conductor bar and the end ring are formed through aluminum die casting.

A bottom view of this type of rotor core is shown in FIG. 10. That is, according to the rotor core of this type, the end rings 151 formed on the upper and lower portions of the rotor core can form an annular end ring of the general type as shown in FIG.

In other words, the rotor of the present form can be summarized as a rotor that forms the end ring after the magnet is inserted. Therefore, the motor including the rotor of the present type is prevented from scattering the magnets due to the top and bottom unit cores, even if the drive is not a direct drive.

On the other hand, in any of the above-described form of the motor, the motor according to the present invention is provided so as not to interfere with the magnet, and comprises an end ring short-circuited with the plurality of conductor bars 122. Of course, the end ring is provided so as not to interfere with the flux barrier 140.

That is, in another form of the motor described above, the flux barrier 140 is not formed at the top and bottom of the rotor core. Thus, the end ring does not interfere with the flux barrier 140. Therefore, the end rings can all be formed of the end ring 151 of a general type, and thus it is possible to minimize the loss due to the end rings.

However, in one embodiment of the motor described above, the end ring 150 is formed after the rotor core is first formed. Then, the magnet is inserted into the flux barrier. Therefore, the end ring 150 should not interfere with the magnet. That is, the end ring 150 should be formed to secure a space in which the magnet can be inserted.

Here, as described above, the larger the radial width of the end ring 150 is, in order to minimize the loss due to the end ring 150. Therefore, in this case, it is preferable that only the minimum flux barrier 140 in which the magnet can be inserted is formed in the uppermost unit core 124.

Thus, in this case, it is possible to form an end ring 150 of the type shown in FIGS. 9 and 11. That is, in particular, it is possible to minimize the loss due to the end ring 150 by increasing the width in the d-axis direction. In addition, since it is preferable to widen the width in the q axis direction, the flux barriers 140 may be more preferably formed to converge toward the center of the rotor as shown in FIG. 9. And the end ring formed in the d-axis direction is preferably formed to be parallel to the q-axis.

In addition, the end ring formed in the q-axis direction is preferably formed to be parallel to the adjacent flux barrier.

Therefore, the end ring 150 in this embodiment is formed in an annular shape in which the width in the radial direction varies along the circumferential direction of the rotor core 123. In addition, the width becomes larger in the q-axis direction than in the d-axis direction.

Hereinafter, the operation of the motor according to the present invention will be described in detail with reference to FIGS. 13 to 15.

The motor according to the present invention can be applied to a fan motor, a compressor, a home appliance, etc., in which a load is basically changed. Hereinafter, for convenience of description, it will be described taking an example applied to the rotary compressor.

In general, a single phase induction motor is used in a rotary compressor. Therefore, such a compressor has a problem of low efficiency due to the characteristics of the single-phase induction motor described above. Therefore, if the motor according to the present invention is applied to a rotary compressor or the like, it is possible to obtain very high efficiency.

On the other hand, in recent years, a variable capacity compressor has been used in which one rotary compressor can be operated with a variable capacity.

For example, there may be a compressor having a variable capacity by varying the amount of refrigerant compressed in one cylinder, and as described in the Republic of Korea Patent Publication 10-2006-0120387 to selectively compress the refrigerant in a plurality of cylinders There may be a compressor that varies.

The latter compressor is provided with a plurality of cylinders in which the refrigerant is compressed, and one motor is driven to compress the refrigerant in some cylinders, but in the other cylinder, the refrigerant is selectively compressed according to the load of the compressor.

Here, the variable capacity of the compressor means that the load of the motor for compressing the refrigerant is variable. Therefore, in the variable displacement compressor, it is possible to obtain a very high efficiency to apply the motor according to the present invention than to apply a general induction motor.

This is because the motor according to the present invention is operated at a synchronous speed in normal operation, and because the motor is always operated at a synchronous speed even if the load is variable, it is possible to considerably improve the motor efficiency in normal operation. In addition, even if the temperature increases because the operation is due to the reluctance torque and the magnetic torque, it is because the loss due to the temperature rise can be minimized.

13 shows the relationship between the starting torque and the capacitor.

As shown, the larger the capacitor value, the larger the starting torque. On the other hand, in order to start the motor, the starting torque must be equal to or greater than a predetermined value. In other words, a starting torque sufficient to overcome the initial motor load is required. Therefore, if the load of the initial motor is large, the amount of starting torque required to be able to start and overcome it must be further increased.

Meanwhile, FIG. 3 illustrates a coil circuit having only one capacitor. In this case, even if the motor load is variable, the capacitor value must be large enough to be able to overcome and start it enough. However, if the load of the motor is small, the use of a large capacitor will cause a loss. Therefore, it is preferable to change the value of the capacitor as the load of the motor varies.

To this end, the motor according to the present invention may include a capacitor connected in parallel with each other, as shown in Figure 14 and 15.

That is, the coil includes a main winding connected with the single phase power source and an auxiliary winding connected with the single phase power source in parallel with the main winding. A capacitor connected in parallel with each other is connected in series with the auxiliary winding. In other words, the circuit shown in FIGS. 14 and 15 is configured to replace the capacitor shown in FIG.

Here, the value of the capacitors connected in parallel to each other is the sum of the two capacitor values when the switch (S) is turned on. Therefore, when the switch is turned on, it has a large capacitor value, and the starting torque can be further increased. On the contrary, when the switch is off, only one capacitor has a value, so the starting torque is relatively small.

Therefore, the switch selectively performs on / off according to the load variation of the motor, but it is preferable that the switch is turned on when the load is large and turned off when the load is small.

For example, when the operating capacity of the compressor can be divided into two cases of large and small, that is, if the load of the compressor can be divided into two cases when the load is large and small, the shape shown in Figure 14 is a large capacity of the compressor It is in the form of operation, the form shown in Figure 15 is the form of operation when the capacity of the compressor is small. Therefore, when a compressor operation capacity is small, since a big capacitor is not necessarily used, it is possible to improve efficiency.

Meanwhile, the capacity of the compressor may be preset when the motor is first started, that is, when the compressor is first started. That is, it may be set to be operated at a large capacity or may be set to be operated at a small capacity.

In addition, it is preferable that the motor is started quickly to operate in a normal state. Therefore, it is preferable that the switch is always turned on at the time of initial start-up of the motor in order to speed up the initial start-up and improve the start-up characteristics. In other words, it is preferable that the switch is always on regardless of the set capacity.

In addition, even when the initial start-up is set to operate with a large capacity, the initial start-up is preferably controlled to be operated with a small capacity. That is, the reason why the large capacity is operated from the initial startup is that the compressor may be unreasonable, and the power consumption may be very high during the initial startup. Therefore, when it is set to operate with a large capacity | capacitance at initial start-up, it is preferable to operate with a small capacity | capacitance until it satisfy | fills a predetermined time or a predetermined condition.

That is, even if the initial compressor is set to operate with a small capacity, it is preferable to start operation with the switch turned on, and to switch off when a predetermined time elapses or a predetermined condition is satisfied.

On the contrary, if the initial compressor is set to be operated at a large capacity, the switch starts to operate with the ON state, but is preferably operated at a small capacity until a predetermined time or a predetermined condition is satisfied. The switch will then remain on and the compressor will run at large capacity unless the operating conditions change.

In addition, the switch may be selectively turned on / off as the capacity varies during normal operation.

According to the present invention can provide a motor that can improve the efficiency.

More specifically, according to the present invention, it is possible to provide a motor that maximizes efficiency during normal operation, in particular by operating at a synchronous speed during normal operation.

In addition, according to the present invention, even when the load of the motor changes during normal operation, the motor can be easily controlled to operate at a synchronous speed at all times, and in particular, it is possible to provide a motor that maximizes efficiency at high temperatures.

In addition, according to the present invention can provide a motor that can reduce the manufacturing cost by having the starting characteristics of the general single-phase induction motor without using an inverter configuration.

In addition, according to the motor according to the present invention can provide a motor that can perform a normal operation faster by increasing the starting characteristics irrespective of the initial load, and can also change the capacitor in the normal operation, the efficiency is very high in normal operation Can provide a motor.

In addition, by applying the motor according to the present invention, it is possible to provide a compressor having high efficiency and very high efficiency in normal operation, and it is possible to provide a compressor that can effectively cope with varying operating capacity.

In addition, according to the control method of the compressor and the compressor according to the invention, it is possible to provide a compressor and a control method thereof that can quickly reach the normal operating state regardless of the initial operating conditions, and can be initially operated without difficulty.

Claims (17)

The rotor is started by induction torque formed by supplying single-phase power to the coil provided in the stator, and rotates at a synchronous speed after starting, The coil includes a main winding connected to the single phase power supply and an auxiliary winding connected to the single phase power supply in parallel with the main winding, And a capacitor connected in parallel with each other in series with the auxiliary winding. The method of claim 1, Any one of said capacitors is electrically connected to said auxiliary winding optionally by a switch. The method of claim 2, And the switch is selectively turned on according to a load change of the motor. The method of claim 3, wherein The switch is turned on when the load of the motor is large, and the switch is turned off when the load of the motor is small. The method according to any one of claims 2 to 4, And the switch is always on at the time of initial start-up of the motor. The method of claim 1, The rotor is, Rotor core; A conductor bar formed along the circumferential direction at an inner outer side of the rotor core to form an induced current; A flux barrier formed inside the rotor core to interrupt a flow of magnetic flux to generate reluctance torque; And And a magnet provided to generate magnetic flux inside the rotor core to generate magnetic torque. The method of claim 6, The rotor is started by the induction torque by the conductor bar, and after starting the motor rotates by the reluctance torque by the flux barrier and the magnetic torque by the magnet. In a variable displacement compressor in which one motor is driven to compress a refrigerant, The motor, The rotor is started by induction torque formed by supplying single-phase power to the coil provided in the stator, and rotates at a synchronous speed after starting, The coil includes a main winding connected to the single phase power supply and an auxiliary winding connected to the single phase power supply in parallel with the main winding, And a capacitor connected in parallel with each other is connected in series with the auxiliary winding. The method of claim 8, Wherein any one of said capacitors is electrically connected to said auxiliary winding, optionally by a switch. The method of claim 9, The switch is selectively turned on according to the load change of the compressor. The method of claim 10, The switch is turned on when the load of the compressor is large, and the switch is turned off when the load of the compressor is small. The method according to any one of claims 9 to 11, Compressor, characterized in that the switch is always on during the initial startup of the compressor. The method of claim 12, And the switch is turned off after a predetermined time when the initial operating condition of the compressor is small. The method of claim 8, And a plurality of cylinders for compressing the refrigerant, wherein the motor is driven to compress the refrigerant in some cylinders, but selectively compresses the refrigerant according to the load of the compressor in the other cylinders. The method of claim 8, And a cylinder in which the compression of the refrigerant occurs, wherein the amount of the refrigerant in which the compression occurs in the cylinder is varied according to the load of the compressor. The method according to claim 14 or 15, The compressor is characterized in that the compressor always starts operation under a small load condition regardless of the initial operating conditions. In a variable displacement compressor in which one motor is driven to compress a refrigerant, The motor, The rotor is started by induction torque formed by supplying single-phase power to the coil provided in the stator, and rotates at a synchronous speed after starting, The coil includes a main winding connected to the single phase power supply and an auxiliary winding connected to the single phase power supply in parallel with the main winding, Capacitors connected in parallel with each other are connected in series with the auxiliary winding, The compressor is characterized in that the compressor always starts operation under a small load condition regardless of the initial operating conditions.

Images